Abstract Flysch is an inter-layer structure with bedding features, which is alternately constituted by sandstone, mudstone, shale and other rocks. Apparent spatial variability is one of the material properties. This paper summarizes the sources of uncertainty of geotechnical engineering, evolution of slope stability analysis method, source of uncertain data and Monte Carlo algorithm, and proposes the simulation method of layered slope uncertainty. Through the analysis of the joint structure of the flysch, we put forward two kinds of simulation methods: explicit joint and implicit joint and make the comparison between the deterministic analysis and the uncertainty analysis. Based on the establishment of the random field of the layered slope, we compare the general slope reinforcement method, including the stability and deformation of gravity retaining wall, bolt, bolt retaining wall and soil nail support. The gravity retaining wall can notably restrain the deformation of the slope, but overestimate the safety of the slope after reinforcement, which is destructible. The control effect of soil nail support, short bolt and short bolt retaining wall on the deformation of the slope is pretty general, but it can provide a relatively secure slope safety, and the slope is more prone to the integral slip. The reinforcing effect of the long bolt and long bolt retaining wall is the worst, which can neither restrain deformation nor provide a reliable security guarantee. For the uncertainty in geotechnical engineering, using structural member to allow more rock or soil to enter working state can effectively reduce the potential risk. 1. Introduction 1.1 Geotechnical engineering uncertainty Slope instability, earthquake, and volcanic eruption are the three major geological hazards in the world (Zhang Y X, 2008). The slope includes the soil slope and the rock slope. Rock mass is often caused by the internal development of weak interlayer intercalation or large faults, joints and cracks (Niu Yi-Wei et al., 2017). It is difficult to simulate the layer rock slope accurately. However, due to the different sedimentary conditions, stress history, weathering and other geological effects, natural soil and rock have significant spatial variability (Chen Zhao-hui et al., 2013). Two aspects reflect this spatial variability. One is physical uncertainty, and the other is cognitive uncertainty. The cognitive uncertainty also includes statistical uncertainty and model uncertainty. The physical uncertainty is inherent in the physical quantity of the rock and soil material itself, which cannot be eliminated but can be desalinated by the quality control. Model uncertainty refers to the difference caused by different constitutive models used in the numerical simulation of geotechnical engineering. Such as Mohr-Coulomb principle and Drucker-Prager principle. Statistical uncertainty should be focused on, because for a specific construction site, during construction period and operation period which are usually much less than the time when a geological change takes place, the parameters and spatial distribution of rock and soil materials in the region will not transform distinctly. In other words, if the researchers can fully investigate the situation of the field, the uncertainty of the geotechnical engineering will be almost eliminated. However, the resources and energy are finite that can be invested in the field survey, which means the short of data will restrict the accuracy of the numerical simulation. Meanwhile, the spatial distribution of the parameters also requires sufficient survey data. In summary, the study of the spatial variability of geotechnical engineering is essential to find a balance between the complexity of the survey data and the reliability of the simulation results. Conditional probability is the tool for stochastic analysis.

Abstract Very often the situation is presented in which the instability causes landslides of rocky blocks in areas that get in the access path of access to the orebody, which is almost impossible to stabilize. Then there is no more way out than to allow the rockfall to occur, of course, looking for possible solutions for their containment and / or reduction, as the fragments that generally fall can reach high speeds and kinetic energy, which makes the phenomenon extremely dangerous and complex to face. Mining operations are increasingly faced with achieving the operational safety ideal of zero harm, while at the same time increasing productivity. The implementation of approved mitigation measures against rockfall in opencast mines is becoming very common, due to the fast installation and cost-effectiveness of such measures. According to the guidelines for rockfall barriers, mines can rely on the approval issued by the EOTA (European Organisation for Technical Assessment). Liability insurance is issued by the suppliers, who guarantee the function of their rockfall barrier systems. In many cases the pit design can be optimized by increasing the slope inclination or reducing the berm width. The solution at Mandai Quarry located at Mandai District in the northern part of Singapore, will be presented in this paper, as a case study. 1. Introduction 1.1 Rockfall barriers Rockfall belongs to gravitative natural hazard processes and endanger frequently human life, infra-structure and settlements. One of the last rockfall events happened some month ago at a main road from Austria to Italy at the Reschenpass causing a fatality as the car was hit (see figure 1). The rockfall event was much larger than the existing rockfall barrier capacity, thus the barrier could not stop the block and it got severely damaged. It was a small rockslide with an estimated volume of around 80 m 3 according to the analysis of the geologist experts. The specialist responsible of taking protective measures face, the following problems: Difficulties in predicting the possible areas from which the landslides originate and the possible trajectories of the fragments The dimensions of the type block, as well as the energy with which they can reach the access path or the area where they are intended to brake blocks. The influence that may be exerted by the material from which the own slope, on which the detachment occurs and which will obviously influence the speed trajectory of the rocks.

Abstract Rock related hazard identification and risk assessment within the confined underground mining space of a tabular mine can be a mastery skill which is sometime difficult to transfer. Failure to identify the lead indicators of ground instability, may unfortunately lead to a major loss, either in revenue, equipment or even a human life. Recent development in the virtual reality space as well as the use of games in education proved to have had a positive impact in the teaching and learning environment. The use of a computer simulated environment in the form of a virtual reality game where an underground worker is given the opportunity to identify the rock fall related hazards and associated risks. This then enables the worker to experience the cause-and-effect of the support design and implementation based on his/her decisions within the virtual game world. The environment is generated with a number of hazards which needs to be identified and taken cognizance of for doing a support design (cause). Given the scenario and available support elements, the candidate then determines the support methodology. The chosen elements are then marked by the trainee within the virtual game world, after which the approach is logically tested in the system. The results (effect) are then visually presented, positive or negative, based on the applied stability design and selected support elements. 1. Introduction New tunnel development in the South African mining industry peaked at levels as high as 800 km per annum in the hard rock industries, whereas the soft rock (coal) industry using a board and pillar layout far exceeded this. These excavations serves various purposes, from linking the stoping areas to the access excavations, to providing fresh air and travelling routes for man and material (including ore and waste). Industry statistics indicate that a high proportion of fatal injuries occur within 5 m from the working face. This is as expected, since the bulk of the workforce is predominately concentrated at the face.

Abstract Huge earthquakes can pose serious risks even for rock tunnels, as evidenced by large earthquakes in the past. In a large earthquake in Japan in 2004, some tunnels suffered severe damages including collapse of their permanent lining, even though the tunnels were constructed in ordinary ground conditions. To mitigate such risks, countermeasures against earthquakes may be used where there are severe conditions such as faults, fracture zones, portals or extremely shallow areas, however, their mechanisms and effects are not fully understood. In this study, static loading tests were carried out assuming a ground deformation mode which simulated horizontal compressive deformation of surrounding ground caused by earthquakes, using a 1/20 scale model. The tunnel lining was laid in a soil container with countermeasures such as rockbolts, carbon fiber sheet on the inner surface of the lining and re-bar of the lining, in order to examine the mechanism of damages to the tunnel and the effects of such countermeasures. In addition, numerical simulations of the tests were conducted to clarify the effects of the countermeasures. The major conclusions of the tests and numerical analyses are: The loading test and the numerical model used in this study can be used to replicate the crown failure of the lining caused by horizontal compressive deformation of the surrounding ground. Rockbolts are less effective than expected in enhancing the load-bearing performance in the case of horizontal compressive deformation of the ground. Carbon fiber sheet and re-bar are potentially effective for avoiding major delamination of lining concrete.

Abstract Slope collapses due to earthquakes and heavy rainfalls repeatedly occurred in Japan, and these disasters often cause serious damages to human lives and infrastructures. Moreover, in many case, slope collapses and rock falls occur at slopes that are evaluated to be stable and the possibility of failure is relatively low, and it is pointed the difficulties to estimate the locations and scales of slopes and rock falls definitely. Therefore, the methods to evaluate locations, scales, time, mechanisms, types and damages with considering uncertainty in a slope stability analysis are required to keep safeties of human lives and infrastructures. Recently, the methods, where the likelihoods of event occurrence are related to the damages for disaster scenarios to be supposed, are attempted in order to estimate the possibilities of the damage. In this study, the disaster scenarios, which are possible processes from occurrence of slope collapses to damages to the road, are constructed to assess hazard to the road as a case study for Echizen Headland in Japan. In Echizen Headland, the national road is located along the coast which is close to steep rock slopes. Rock falls or small scale collapses have occurred every few years in this area, and large scale slope collapse, where the volume of collapsed rock masses amounted to 1100m 3 , occurred in 1989. The disaster scenarios are estimated by using the results of DDA (Discontinuous Deformation Analysis) for the slope collapses and rock falls. The possibilities of damage to the road are estimated from the relations between likelihood of event occurrence and volume of collapse.

Abstract Following the 22 February 2011 earthquake in Christchurch significant rockfall, cliff collapse and landslides occurred around the Port Hills. Rocks from numerous bluff systems and individual outcrops above Evans Pass Road fell and collapsed ending up on or impacting the road. Evans Pass Road is the only route out of Sumner if Main Road, below the 60 to 70 m high cliffs at Peacocks Gallop, is damaged or impacted by events such as rockfall and cliff collapse. This report focuses on the processes undertaken to reopen Evans Pass Road to the public. The main stages of reopening the road were rockfall and source rock mapping, determining risk assessment criteria and assigning risk ratings, determining remedial options, undertaking the remediation, and reviewing and reassessing completed works. Remediation methods employed above Evans Pass Road included scaling, rock rolling, low and high energy blasting, and mechanical restraint; the reasons for using these methods at specific locations are discussed.

Abstract India has 2% of the total land area of the world but supports morethan 17% of global population. Due to diverse geological environment and geodynamic processes, the country faces several types of geohazards including earthquakes, landslides, tsunami, glacial lake outburst floods, landslide dammed lake out burst floods etc. that affect the lives, economy and environment adversely. About 2% of the gross domestic product and 12% of the revenue is lost on an average annually due to various disasters that also kill several thousand people. Approximately 59% of the land territory is affected by earthquakes and falls in seismic zones III, IV and V where seismic intensities of VII, VIII and IX respectively may be expected. The northern part of the country comprises Himalayan belt that is geodynamically active, climatically sensitiveand severely susceptible to landslides and flash floods besides the earthquakes. Due to changing climatic conditions, rising population and unsafe development / urbanizationpractices, the incidences and impacts of these geohazards are increasing. Keeping the above context in mind, the national disaster management authorityin Indiahas made attempts to assess the types and levels of thesedisasters that affected the country in the past and identified potential risks to different vulnerable elements based on inputs from various sectors and disciplines. The professional geologists and engineers have contributed greatly towards better scientific understanding of the geohazards and formulating effective plans forsafer sustainable development. The national level policy, guidelines, plans, programmes, projects and procedures / regulatory measures focusing on technical, administrative, financial, legal and socio-cultural issues, have targeted integration of disaster risk reduction with development. The paper discusses the national initiatives with particular reference to earthquakes and landslides with a view to share and exchange the experiences in disaster risk reduction. It will help in learning good and bad practices for promoting disaster resistant / resilient development and nurturing a culture of risk avoidance, prevention, mitigation and preparedness at global level.

ABSTRACT This study introduce a new risk assessment system based on Business Continuity Plan(BCP) for underground limestone mine. This system is systematic and simple to manage the risks by using RALM jk (Risk Assessment of Limestone Mine). Here, sub notation of ‘j’ represents mining processes and ‘k’ represents possible risks in those processes. Approximately 60 limestone mine risks were obtained from Disaster Yearbook and Mining statistics. Risks obtained were classified by five different mining processes which are blasting & drilling, digging, loading & haulage, crushing & classifier, and maintenance respectively and then reduced the number of risks from 60 to 26 based on their characteristics and similarity in mining process. After allocating risks in RALMjk, risks were assessed. To do this assessment, this study used four different risk indexes which are probability, casualty, facility loss, and discontinuity respectively with seven different risk levels. After finishing these works, the survey was done by the experts to assess risks. The results showed that risks could be classified into four groups of cluster depending on the level of probability index versus average level of other indexes. It also introduced the most possible risks at limestone mine is RALM 21 which is a roof-fall and rock-fall in digging process.

ABSTRACT Slope stability in open pit mining industry is one of the important issues at this time given that most mining companies in Indonesia to increase production. As a result, the mining companies to do the widening and deepening of the excavation. Increasingly wide and deep open pit excavation is done, then of course the greater the risk that would arise, or the increasing uncertainty in the factors that influence the stability of open pit slopes. The factors that lead to the risk of slope kelongsoran include physical and mechanical rock properties, groundwater conditions, rock mass characterization, as well as the existing structure on the rocks. This paper described risk approach of slope failure based on probability of failure (PoF) and the consequences on a case study mineral X in Indonesia. PoF is determined from input parameters and FoS distribution, while the consequences is based on the results of field observations. Certainly the results of this approach can provide a decision on the slope stability conditions, thereby reducing the greater effect of risk of slope failure.

ABSTRACT Based on a series of laboratory tests and in situ monitoring and tests at deep tunnels excavated by TBM or D&B method, mechanism of evolution process of different types of rockburst, including strain burst, strain-structure slip rockburst, immediate rockburst and time delayed rockburst, and has been understood. The digital borehole televiewer and seismicity monitoring system have been used to obverse cracking initiation and propagation process during rock burst evolution process. A warning system based on micro seismicity has been established for warning of various intensities of rockbursts, such as slight, moderate, intensive and extremely intensive rockbursts. The probability with the intensity of rockburst is also given. The strategy for excavation and support design has been recommended for various intensities of rokcburst before the excavation. The strategy for dynamic control of rockburst evolution process is also proposed according the warning. The methodology has been successfully applied to rockburst risk reduction for deep tunnels at Jinping II hydropower station. The results have illustrated applicability of the proposed methodology and techniques on rockburst.

INTRODUCTION The construction of tunnels and the development of tunnelling methods in a country are strongly influenced by the Geographical situation, topography, existing infrastructure and buildings, environment, natural resources, geology, hydrology, the demand for underground works, Political, social, economical situation, Legal status and competence of owners, the availability of qualified workforce, mining traditions and contractual attitude. The protection of the population against emissions as well as the protection of the environment and natural resources require an increasing number of large underground constructions. In terms of tunnelling, the geology in Austria is generally difficult and tends to change rapidly along the tunnel route. Tunnelling in the Alps means facing a high overburden and, in places, heavily squeezing rock. Further more tunnelling in urban environments is gaining importance. After the mid-fifties of the last century new materials, namely shotcrete and rock anchors, replaced the old timber support and the masonry lining was abandoned for a permanent lining of in-situ concrete. In addition, the waterproofing quality of tunnels was considerably improved with the standardized use of synthetically membranes and fabrics. At this time Austria had a number of brilliant engineers like Rabcevicz, Muller, Patcher, Loafer, Seeder, ital. who greatly influenced and promoted the development of tunnelling in Austria by innovative ideas. Most important was the development of ATM (New Austrian Tunnelling Method), which introduced the observational approach in tunnelling. Owners experienced in tunnel design and construction together with specialised contractors developed an On-site decision making procedure, which became common practice in Austrian tunnelling. The technological development and the engineering practice in tunnelling paved the way for new theoretical explanations to substantiate an economically beneficial design approach. The Austrian way of tunnelling foresees immediate and joint decisions by both partners within the contractual frame work. This ensures an immediate and effective response to changes in ground conditions. The ATM needs qualified and experienced owners, designers and contractors, qualified and authorised engineers on site, as well as a qualified and experienced workforce and a suitable contractual model. An important feature of the Austrian tunnelling community is to ensure a good cooperation between all parties to a contract. Technical questions regarding safe, fast and economical tunnelling take priority over contractual considerations. This approach is of general benefit to all parties. It is based on a profound technical expertise and a genuine willingness to compromise. As a rule tunnelling works in Austria are executed on the basis of unit price contracts. The Austrian way of tunnelling foresees immediate and joint decisions by both partners within the contractual frame work. This ensures an immediate and effective response to changes in ground conditions. The ATM needs qualified and experienced owners, designers and contractors, qualified and authorised engineers on site, as well as a qualified and experienced workforce and a suitable contractual model. An important feature of the Austrian tunnelling community is to ensure a good cooperation between all parties to a contract. Technical questions regarding safe, fast and economical tunnelling take priority over contractual considerations.

Abstract: Tunneling method selection is a critical point and a strategic issue in the planning stage of a tunneling project. Compatibility of a selected tunneling method with the geological and geotechnical conditions is crucial to success of a tunneling project. On the other hand, use of a decision-making process is inevitable with regard to many geological and geotechnical variables and uncertainties and also unpredictable ground conditions during tunneling operation. So, use of an efficient decision making technique which can take into account several criteria in such conditions is necessary. This paper develops an evaluation model based on the analytic hierarchy process (AHP) and the technique for order performance by similarity to ideal solution (TOPSIS), to help the engineers in tunneling industries for the selection of optimal tunneling methods in a fuzzy environment. The fuzzy-AHP is used to determine global weights of the criteria and fuzzy TOPSIS method is used to obtain final ranking of alternatives. This approach is applied to select optimal tunneling method among six tunneling techniques including open TBM, double shield TBM, single shield TBM, roadheader, drilling & blasting and hydraulic hammer in Zagros water transfer tunnel of Iran. Finally, double shield TBM was selected as optimal tunneling method in Zagros water transfer tunnel of Iran. 1. Introduction Selection of the proper tunneling methods for use in various ground conditions is a very delicate and important part of planning a tunneling project. This is because this decision is almost irreversible and if the selective tunneling method be not suitable for the ground conditions, it can cause major delays, could be detrimental to the safety of the crew and personnel, and ultimately could bring the project to a halt. Obviously, accurate characterization of the ground using surface and subsurface investigation will allow the designers to foresee the potential problems and select a method that can cope with the anticipated conditions. This often means selecting a method that can offer optimum performance in the given conditions, and sometimes adding special features and devices that could provide the flexibility and capability to mitigate adverse ground conditions. In brief, selection of a proper tunneling method with the right technical specifications and functionalities is important to ensure the speedy, safe, and successful completion of the tunnel project within the requirements of the contract. However, by its very nature, subsurface investigation and ground characterization can be all but certain. There are multiple levels of uncertainty involved in ground characterization starting from the location of the borings, formations or layers that could be missed in the drilling program, proper logging and characterization of the lithotypes, accurate measurement of the rock properties in the field and laboratory testing, issues of groundwater and their sources, in situ stresses, and so on [1]. This indicates the need for additional tools for assisting the decision making in the design and construction stage. Typical tools at the engineer's disposal are statistical methods, systematic risk assessment methods and, more recently, artificial intelligence (AI) approaches such as neural networks and fuzzy logic.

Abstract: Constructing mountain roads in harsh terrains is a challenge to the engineering and development of southwestern Saudi Arabia. Al-Baha 32 km-mountain road is constructed at steep slope rock masses, where many rockfalls incidents were experienced. A 100 m long portion of the road, suffers from frequent rockfalls. The rock masses are mainly igneous rocks of medium to low quality. The rock slope-cut has no bench for 20 m, 70°–90° inclination, and 30 m height. Absence of ditches and support systems aggravates the daily road conditions. The RocFall computer program was utilized to perform the risk analysis on such steep man-made and natural rock. Geotechnical parameters such as block size, seeder points of blocks falls, slope angle, restitution coefficients, and slope roughness were used to identify properties of the potential and fallen rock blocks such as: bounce height, kinetic energies (total, translational, and rotational), and translational and rotational velocities. The program modeled the proposed location and energy of the rock blocks barrier's heights and locations, collectors, and proposed slope safer redesign. The results of the study provide a solution to prevent rockfalls, and could be applied at similar conditions. 1 INTRODUCTION Slope failures, landslides and rockfalls are frequently occurred on mountain roads, at rugged terrains. One of the most difficult terrains in western Saudi Arabia is Al-Baha descent, which is characterized by sharp cliffs and high elevations which reaches above 2,000 m above sea level. The highest elevation at the descent is about 2,200 m (at km 0) above sea level, where the difference in elevation from the highest to lowest elevation is about 1,750 m, the difference is about 450 m at km 32. The descent lies between longitudes 41°25"E and 41°29"E and latitudes 19°47"N and 20°01"N; see Fig. 1. Al-Baha escarpment 50km-road starts southwest of Al-Baha city, and runs through Al-Baha descent. The road connects the highlands where Al-Baha city is located with the lowlands at Al-Mukhwah town. Along this distance, natural slopes in addition to many man-made slope cuts and engineering structures are located. Al-Baha descent includes three distinct geomorphologic terrains: a dissected upper plateau of low mountains and hills, a precipitous escarpment, and a low-lying coastal plain (Fig. 2). 2 BRIEF GEOLOGIC HISTORY The geologic history indicates that the escarpment resulted from a 3000 m lowering of Tihama Coastal Plain during the Tertiary opening of the Red Sea. Al-Baha descent's road is contained almost within a structurally controlled narrow valley, called Wadi Rash. Steep tributaries start from the escarpment ridge, and radiate out from the wadi head and cut deeply into the valley sides and escarpment face. Al-Baha region is underlain predominantly by a north-south trending belt of Precambrian schistose rocks comprised predominantly of fine grained mafic to intermediate extrusives, intrusives and pyroclastics with minor intercalations from clastics and metasediments [1]. The majority of the rocks at the descent area have been subjected to greenschist and amphibolite facies metamorphism [2].

Abstract: The proposed alignment for the Ipswich Motorway Upgrade (IMU) from Dinmore to Goodna west of Brisbane, Queensland, Australia, traverses over three abandoned underground coal mines from different eras of mining (from the 1860's to 1987).The underground coal mines vary in depth/cover, age, and hence the mining methods used from Welsh bord and pillar mining using chiefly hand tools, through to modern mechanical mining methods. The three mines pose different risks to motorists from potential mine collapse/subsidence during the motorway's 100 year design life due to varying overburden cover, geometry, subsoil/rock conditions and proximity to the motorway. This paper presents a case study of a risk assessment-based approach used to determine the requirements of remediation (type and extents) to ensure safe driving for motorists in the event of potential mine subsidence. The risk assessment was undertaken at the various design stages based on an evolving knowledge of mine geometry and extents as the investigations proceeded in-parallel with the design. The decision-making process at each design stage was managed by assessing the risks associated with mine subsidence based on the information then available. 1.INTRODUCTION The Ipswich Motorway Upgrade – Dinmore to Goodna (running in an East-West direction, refer Figure 1) involves the upgrade of 8km of constrained urban motorway from four lanes to a minimum of six lanes and also includes two motorway-to-motorway interchanges. This is one of the largest roads projects undertaken in Queensland, Australia, with estimated costs of AUD1.95billion. The motorway upgrade is part of the national and regional infrastructure investment strategy to provide the transport corridor for the growing urban population west of Brisbane. The upgrade is within a largely confined corridor, thus requiring careful planning for implementation whilst maintaining connectivity for up to 80,000 vehicles per day through the corridor. Numerous demolition (of some of the existing infrastructure) and construction stages are required with temporary re-alignment of live traffic lanes throughout the construction period. The proposed alignment traverses immediately over the relatively shallow (20 to 35m cover) Goodna mine (mined from the 1860's to the 1920's), skirts over a section of the New Redbank mine (1920's) and traverses in close proximity over the Westfalen No. 3 mine (1970's and 80's), both with 70 to 120 m of cover. The presence of these mines has complicated the design and construction sequence. Because of safety in design and construction considerations, anymine remedial works would need to be constructed prior to the civil and structural works, requiring remedial works to be on the critical path of the construction program. The Queensland Department of Transport and Main Roads (QDTMR) established the Origin Alliance (OA) comprising the QDTMR (client), Abigroup, Fulton Hogan and Seymour Whyte (contractors), and SMEC and PB (design consultants) to deliver (design and build) the proposed motorway upgrade through an alliance framework. Origin Alliance commenced work in June 2008 with an expected project completion date of 2012. Prior to OA's engagement, only preliminary investigations and risk assessment was carried out for the abandoned underground mines.

SYNOPSIS: Underground cavern for the energy storage (oil and gas) has been constructed because it has a merit in the cost of maintenance and in the durability through the long-term service period. However, today, rational structures in the construction, the operation and also the maintenance are demanded. And in order to maintain the function and the performance that is set as the initial condition, preliminary study based on the result of examination considering the time dependent behavior of the structure is necessary. Here, the current state of the method of evaluating the cost and the performance of the underground structure are summarized and problems are pointed out based on the concept of the life cycle cost. 1. INTRODUCTION Now a lot of structures are constructed in the underground. However, it is said that if they have the same function and the performance, those construction cost is more expensive compared with that of constructed on the ground. In Japan, mountain method tunnels for the rail and the road have been constructed because of their restricted linear planning condition due to steep geographical features. Also a large-scale underground cavern for a pumping type power plant has been inevitably constructed from the condition demanded on its function. On the other hand, underground caverns for energy storage, such as gas and oil, have been planned and constructed because of the economic advantage. Namely the total cost during a long service period is not so high due to the long-term durability and maintenance free of the underground. For a long time, underground structures such as tunnels and caverns have been considered as eternal structures which do not need large-scale repair and reinforcement all over their service period. However that situation is changed by the accident where a part of the tunnel lining concrete fell down in piece in 1999. As a result, following reasonable facts were recognized again. □ The performance of the structure decreases with the time passage. □ The load considered in the design of the structure is to have the uncertainty, so it is possible that the load exceeds the predictions at the design stage during the long term service period and this may cause the damage or the collapse of the structure. In other words, it became clear that the preliminary examination considering how to maintain an initial function and performance is necessary. Also the appropriate action at each stage of the design, construction and the maintenance is necessary even for the Fig.1 Cavern for energy storage underground structure that consists of concrete and rock. Then there is no merit in the underground structure? The purpose of this paper is to summarize a current problem concerning the evaluation of the safety and cost concerning the underground structure and to grope for new approach on them. 2 ASSET MANAGEMENT OF CIVIL STRUCTURE In Japan, a lot of infrastructures constructed at a period so-called high growth of economy after the 1960's begin to cause various troubles to their functions after about 50 years.

ABSTRACT Potential geotechnical hazards make it difficult to select an appropriate TBM in adverse and difficult ground conditions. So, use of an efficient decision making technique which can take into account several criteria in such conditions is necessary. Analytic hierarchy process (AHP) is one of the most commonly used MCDM methods, which integrates subjective and personal preferences in performing analyses. However, AHP involves human subjectivity, which introduces vagueness type uncertainty and necessitates the use of decision-making under uncertainty. In this paper, vagueness type uncertainty is handled using fuzzybased techniques. The traditional AHP is modified to fuzzy AHP using fuzzy arithmetic operations. The efficacy of the proposed F-AHP was demonstrated through dealing with the selection of the most appropriate rock TBM in adverse geology. Based on the analysis results, both the single and double shield TBMs have the same preference for selection in difficult ground conditions. 1. Introduction Generally when mechanized tunneling is selected as construction method, the most important problem is often related to selection of the most appropriate TBM and its performance prediction. Many investigators have studied risk and TBM selection issues separately. Among them, the efforts of Nord and Stille [1] introducing effective parameters in tunneling techniques selection, Einstein et al. [2] introducing the decision aids in tunneling, AITES-ITA Working Group No. 14 [3] introducing standards for TBM selection, Bieniawski et al. [4] presenting rock mass excavability (RME) indicator when selecting excavation technique should be noted. Only few studies on TBM selection focusing risk assessment have been reported. This is undoubtedly due to the complexity and frequency of effective decision variables. More recently, Shahriar et al. [5] proposed a methodology for rock TBM selection in difficult ground conditions by assessing geotechnical risk. This approach is now extended to fuzzy AHP methodology as a decision support aid. The primary objective of this approach is to present a methodology to guide decision-making under vagueness type uncertainty. This task is achieved by proposing a risk-based fuzzy analytic hierarchy process (F-AHP). The efficacy of integrating fuzzy-based technique to AHP is illustrated using an application of selecting three rock TBMs in difficult ground conditions. 2. Essences of fuzzy AHP AHP introduced itself as an approach for evaluating complex multiple criteria alternatives involving subjective judgment. A decision-maker determines his/her weights by conducting pairwise comparisons between criteria. Though the aim of AHP is to capture a decision maker's knowledge, the conventional AHP cannot fully reflect the human thinking style. Linguistic and vague descriptions could not be solved easily by AHP until the recent development in fuzzy decision-making [6]. Fuzzy set theory, first proposed by Zadeh [7], and the subsequent fuzzy decision-making methods offer a more natural way of dealing with these preferences instead of exact values. The traditional AHP does not take into account the uncertainty associated with the mapping of one's perception to a number [8].

Abstract The conceptual idea behind the observational method can be described as an active process where we will be able to modify and adapt our design to actual geological conditions by means of additional information coming from observation during construction. This will in many cases give a more economic design. A successful application must be based on that all parties involved in the project acknowledge the conceptual idea in which an understanding of how geological uncertainties can be reduced by observations is essential. Further formal and practical requirements must be fulfilled. The contractual prerequisites must also be established. The observational method must also have a clear role to play in the execution phase and must be integrated into the production process. In the paper the connection between the observational method and modern developments in probabilistic method 1. Introduction Design of underground openings includes to deal with uncertainties related to the sub-surface conditions. Safety issues and providing underground structures with an economic design taking the geological setting into account was the key considerations when the observational method was formulated by Peck [1]. The main contents of the observational method had been presented earlier by Terzaghi and Peck [2, 3]. The term ‘active design’ is used in Sweden to denote a methodology for dimensioning complex structures in rock. This approach has great similarities with the observational method. The term was introduced for emphasizing that design is an active part of the construction process. The basic elements of active design comprises to establish a preliminary design, plan for contingency measures in case of unforeseen events, perform relevant observations during construction and, accomplish a final design that complies with requirements by means of active adaptation to the actual conditions. Stille describes how active design has been used successfully in a number of complicated Swedish rock engineering projects [4]. The observational method is one of the designated design methods in the new Eurocode, EN 1997–1:2004[5]. From an engineering point of view this allows the designer to employ formal approaches towards design uncertainties as well as towards results from monitoring and observations made during construction. However, the theoretical background as well as the contractual aspects is not described in the code, only the formal requirements for applying the method is given. Quantifying uncertainties and its dependency on the degree of information is a challenge, but nevertheless a logical extension of the observational method. Connecting the observational method to modern developments in probabilistic methods will provide a firm base for its application [6, 7]. This issue is a central part of this paper. The aim for this paper is to present an overview of the observational method and its application in rock engineering. A successful application must be based on that all parties involved in the project acknowledges.

Abstract The exhaustion of coal resources near the surface forces the panels to go deeper into higher stressed and more geologically complicated environments. Implementing tougher safety regulations requires semi to full mining automation to reduce the number of underground miners. All of these changes pose greater challenges for mine operators striving to achieve high production while maintaining favourable mining conditions. Weak geological structures, such as faults and fracture zones within a longwall panel may have great impact on the stability of the coal and rock mass. The reactivation of the structures and induced fractures during mining can significantly change the rock mass integration and stress conditions in the roof and floor, and cause the roof rocks to collapse near the working face. Understanding the fault reactivation and fracture development is thus crucial for the control and prevention of impending problems. Microseismic monitoring techniques developed by CSIRO has applied to a number of longwall coal mines in Australia to monitor fault reactivation and rock fracturing ahead of mining face during production. This paper presents the microseismic techniques used for this application and results obtained at the mines. It is demonstrated that fault reactivations and rock fracturing associated with mining can be efficiently observed remotely and in real-time using an array of seismic sensors. The microseismic results provide very useful information for longwall coal mine operators for risk management and production control. I. Introduction Longwall mining has become the most widely used mining method for underground coal mines due to the productivity that can be achieved. Typically, longwall panel are 100–300 m wide, 1,000–3,000 m long and 2.8–4.5 m high (coal mining height). In Australia, the depth of the coal seam being mined is typically 150–500 m below the ground surface. Along the two sides of the panel are pairs of parallel tunnels (roadways) for transportation and ventilation. At the mining face a cutting drum (shearer) moves back and forth across the panel. The roof strata of the coal seam near the face are supported by hydraulic shields which are moved forward with the progression of the mining. Behind the shields, the unsupported roof strata collapse to form what is known as the goaf (Figure 1). The trend of longwall coal mining goes to longer and wider longwall panels for more production. The exhaustion of coal resources near the surface forces the panels to go deeper into higher stressed and more geologically complicated environments. Implementing tougher safety regulations requires semi to full mining automation to reduce the number of underground miners. All of these changes pose greater challenges for mine operators striving to achieve high production while maintaining favourable mining conditions. Weak geological structures, such as faults and fracture zones within a longwall panel may have great impact on the stability of the coal and rock mass.