In recent years, the underground space has overcrowded with the overcrowding of urban areas. Therefore, the adjacent construction of underground structures is increasing. In such a construction, an influence of the construction of a new structure on the existing structure has to be considered. In order to minimize the influence on such existing structures, application of the underpinning method is expected. The underpinning method is a construction method that attempts to reduce the influence on the existing structures by excavating the ground around existing structures with constructing, rebuilding, and reinforcing new foundations. This study focuses on the underpinning method using pipe jacking. In order to ensure the effectiveness of the underpinning method, 3D finite element analysis was carried out. In particular, four major considerable factors were discussed: the influence of pipe presence, comparison of using conventional underpinning and pipe jacking, the influence of the distance between the pipes and new structure, the influence of pipe length. Based on the numerical results, it is possible to reduce the vertical displacement on the existing structure by using the underpinning method using pipe jacking. Additionally, the underpinning method using pipe jacking is effective to reduce the displacement over a wide range compared with the conventional underpinning method. Furthermore, the influence on the existing structure and the surrounding ground can be minimized by adopting the proper distance of pipe length and the space between the pipes and the new structure. 1. Introduction In recent years, overcrowding has occurred due to the factors such as population increase in urban areas. Various structures are complicated in the underground space and the underground space is overcrowded along with the overcrowding of urban areas. Therefore, adjacent constructions of underground structures are increasing in the underground space of urban areas. Adjacent construction of the underground structure is the construction such as adding an underground tunnel to the surroundings of the drainage pipeline. In adjoining constructions of such underground structures, it is a problem that the influence on existing structures becomes particularly large when constructing new structures. Application of the underpinning method is expected as a construction method to reduce the influence on existing structures. Recently construction methods such as cutting edge jacking method, and shielding method are mainly applied when constructing an underground structure. (Matsumoto et al., 2015) These construction methods are required to occupy a wide range of construction area, long construction period and high cost, so it is difficult to apply those construction methods in urban areas. Therefore, pipe jacking method which is non-cutting technique is required as an effective construction method in urban areas (Japan Tunneling Association, 1997). For the above reasons, construction of the underpinning method using the pipe jacking method is expected for adjoining construction of underground structure.

Abstract The study introduces two optimization design cases for construction and mining equipment. One is the optimization of button design on a drill bit face of rock drill machine; the other is the design study of pick cutter arrangement on the cutting head of a roadheader. Rock drilling machines are commonly used for surface drilling, tunnel excavation, and underground mining. Drill-bit buttons need to be designed to increase the rock drilling efficiency. The optimal button arrangement of a drill bit and its operating condition were proposed to improve the drilling efficiency. A new evaluation method of the button arrangement that utilizes the superimposed impact area, the blank area and the moment as quantitative indices is introduced to evaluate an effect of button impacts on the rock surface. Pick cutters are core tools for roadheaders, as they directly indent and fragment the rock and minerals. A lab-scale linear cutting machine was manufactured to investigate the rock-cutting mechanism and a range of design factors: such as attack angle, skew angle, and pick spacing with cutting depth. Eventually, we proposed design conditions for the cutting head to achieve efficient rock cutting with minimized specific energy. 1. Introduction In the civil and mining industry, the rock drill machines are widely used for a variety of drilling applications in construction sites, quarries, and mines. The drill bit is one of the most important parts of these machines, primarily as it directly impacts on the rock surface. Optimal bit design specifications (e.g., button material, button shape, button size, button arrangement, bit head design, and internal flushing channel design) are needed to improve drilling rates and efficiency. Among these parameters, the design of drill-bit button arrangements is especially important as these buttons directly drill into the rock. This paper investigates the effect of button arrangement on drilling efficiency.

Abstract KURT is a generic URL with a total length of 551 m and six research modules. The maximum depth of the tunnel is about 120 m from the surface. The host rock is granite, which is considered as a potential host rock type for HLW disposal repository in Korea. Various in-situ tests and experiments have been carried out since 2007, and tracer test and In-DEBS are two representative experiments that are being carried out in KURT. The research experiences gained using KURT are providing important information to validate the safety and feasibility of the deep disposal system. KURT is currently playing a major role in the development and demonstration of the proposed disposal concept and technologies, and particularly public acceptance. 1. Introduction KAERI (Korea Atomic Energy Research Institute) has developed a deep geological disposal system for high-level radioactive waste (HLW) through a long-term research project since 1997. KAERI is currently developing an advanced Korean reference disposal system (A-KRS) and its related technologies for HLW from the advanced fuel cycle system, which include pyro-processing of PWR spent nuclear fuel (KAERI, 2011). To dispose HLW safely in geological formations, it is necessary to assess the feasibility, safety, appropriateness, and stability of the disposal concept at an underground research laboratory (URL) constructed in deep geological formation as the desired host rock. The Planning Committee for the Korean Nuclear Energy R&D Programme decided to construct a small-scale generic underground research facility at the KAERI site to experimentally investigate the proposed disposal concept and relevant technologies in underground conditions in 2003. The phase I facilities of the KAERI Underground Research Tunnel (KURT) were constructed in November 2006 based on the decision, and various in-situ tests and experiments have been carried out since 2007 (Cho et al., 2008). The extension work for the planned tests and experiments of the phase II programme was completed in 2015. KURT is a generic URL, and not a potential site for waste disposal. The main geology of the KURT site is crystalline rock such as granite, and it is not allowed to conduct any experiments using radioactive nuclides in KURT. In this paper, the current status and representative activities of KURT, and KURT's role in HLW disposal technology development in Korea, are described.

Abstract Under the conditions of unfavorable topography and geology, the construction of the mountain tunnel may pose a significant risk of tunnel collapse and large deformation accidents, which will cause casualties and great economic losses. Then how to predict the occurrence of tunnel collapse is particularly important. We usually predict tunnel collapse based on the tunnel deformation. In the process of tunnel construction, there are many factors related to the tunnel deformation, such as the rock mass classification, tunnel dimensions, groundwater, ground stress, construction methods and process, climate, management methods, etc. And they will affect each other as well. Therefore, some soft science technologies often are adopted to predict the tunnel deformation, such as artificial neural network, support vector machine (SVM), grey theory, etc. Support vector machine (SVM) has shown a remarkable generalization performance. But there is no determinate theory or method to select the internal indexes of the SVM model for tunnel deformation prediction at present. This paper establishes several tunnel collapse prediction models using support vector machine (SVM) according to the 150 cases we collected. Among them, 100 cases are used as train set to establish the SVM prediction models, and the rest are used as test set. Through a series of tests, several indexes which can improve the prediction accuracy are selected among the all indexes mentioned above. Combined with these selected indexes, this paper establishes an improved SVM deformation prediction model and tests the accuracy of the model with the data from Yima mountain tunnel. In order to assess the influence of those factors which are difficult to quantify, this paper takes the Hurst exponent into consideration in the support vector machine deformation models. And it indicates that the deformation prediction accuracy can be improved by analyzing the Hurst exponent of the tunnel deformation sequence. Furthermore, the accuracy of the improved deformation prediction model can satisfy the need of actual projects.

Abstract We present an optimized training and prediction model for Rate of Penetration (ROP) forecasting using on-line artificial neural network (ANN) in real-time. The technique aims to assist decision making on drilling operations by predicting ROP under a given set of drilling conditions. The scenario modeler relies on real time drilling data analysis, and it is capable of handling cumulative information analysis in real time for ROP prediction within the same well, but also can consider drilling data gained from other fields under similar conditions. The real time prediction model has been applied to drilling data coming from a geothermal project of over 4 km depth, located in the Pohang, Republic of Korea. The observed results with respect to data intervals or sections set the basis for further adjustments to the model, and encourages its use in different drilling situations. 1. Introduction ANN have been applied to a wide variety of field research areas that include computer vision, speech recognition, and petroleum engineering (Bilgesu et al., 1997). Especially, in the aforementioned field, ANN have been used for ROP forecast (Gidh et al., 2012). It has been shown that this technique is dependent on the size and accuracy of the input parameters, and in general the more number of data points, the better the results. Its ability to consider more drilling parameters into the model makes it advantageous (Monazami et al., 2012). During ANN learning phase, a selected group of input parameters are provided to the model and they serve to train the algorithm. Two basic types of learning modes can be mention, On-line and off-line training, and they distinguish from each other basically on the training cases are managed after training (Shin 2001). In on-line training, the provided input parameters are discarded after being processed, however the weights are updated. Owing to the accumulative manner the drilling data is generated in the field, this work explores the applicability of an artificial neural network with an on-line training mode for ROP prediction especially in subsequent drilling sections within the same well.

ABSTRACT: Taking the project in China as background, established a physical model experimental platform to simulate the cavity construction using the similar theory. The influence of interlayer to the cavity construction was studied. It was found: when the interlayer exists, the flow field becomes more complex; and the brine distribution besides the interlayer will be changed. Thus the dissolution of salt rock besides the interlayer was affected which results the triangle insoluble inclination appearing on the top of the interlayer, making the cave building inefficient and being not conducive to the cave shape control. It is the key to make the interlayer reasonable collapse in cavity construction. 1 INTRODUCTION Rock salt is a kind of soft rock, and it has excellent physical and mechanical properties of the low permeability and good self-healing ability which make it to be widely recognized as the ideal energy underground storage sites. The underground energy storage of Salt rock has been built and accomplished successfully widely in many countries. Foreign researchers have studied on the mechanism of flow and controlled dissolution of salt in solution mining, the solubility properties of rock salt, and the shape control techniques of cavities in salt formation for underground gas storage (Hossein & Jessen 1964, Ehgartner et al. 2009, Fuenkajorn 2010). Relative to the foreign large salt dome landscape, there are many layers of mudstone in salt beds which has a thin single layer. And such special geological conditions increase the difficulty of solution mining in the control of cavity shape and stability of the cavity, making caverns irregular shape and poor mechanical properties, which is less than the expectations of the desired effect. The collapse of the interlayer may damage the casing of the cave, and influence the shape of the cavity, which is a trouble for cavity building.

ABSTRACT: Based on the engineering background of No. 2 Xi'an Line metro shield tunneling, with a tunnel of 6 m diameter and 15m depth as the research object. The stress ratio curve of surface horizontal displacement and supporting is obtained by numerical simulation. Limit supporting stress ratio of the excavation face is between 0.1–0.15. Meanwhile, the research studies the plastic zones changing process at the excavation face from stability to destruction. With the decrease of excavation face supporting stress, the front soil displacement of the excavation face is increasing and the plastic zones in the front of the excavation face is expanding from the top to the earth's surface. When the supporting stress approaches the limit supporting stress (supporting stress ratio is 0.15), the diffusion area of plastic zones and the plastic zone expanded to the earth's surface, and the excavation face become unstable. By setting the horizontal and longitudinal monitoring lines, the research studies the changing of surface subsidence under different supporting stress ratio. For the transverse deformation, the smaller the supporting stress ratio is, the more obvious the settling tank is. While the supporting stress ratio is greater than 1.0, the surface uplifts. The greater the supporting stress ratio is, the more obvious the uplift is. For the tunnel longitudinal deformation, while the supporting stress ratio is greater than 1.0, all the ground uplifts, while the supporting stress is less than 1.0, the surface in the front of the tunnel subsides, as well, the surface in the back of the tunnel uplifts. When the supporting stress ratio is less than 0.2, all the ground subsides. While the supporting stress ratio is equal or less than 0.2, it can be clearly observed that about 5 m in the front of the tunnel is the maximum subsidence, by which a settling tank is formed. INTRODUCTION SUSTAINABLE DEVELOPMENT With Chinese rapid development of social economy, the urbanization process is increasingly sharpened, the use of various ground resources tends to saturation, and the development and utilization of city underground space resources has become an important direction of social sustainable development. Improving for construction speed and having small influence on the environment, shield construction, as a special machine of tunnel construction, is widely used in the city underground tunnel construction, such as the subway and underground pipeline construction in Shanghai, Beijing, Nanjing, Guangzhou, Shenzhen, Tianjin, Chongqing and so on. But it is also a tough question to make a rational selection of the excavation face support pressure in engineering application. Xi'an Metro Construction applies shield tunnel construction method for the first time in loess area.

ABSTRACT: Blast tunneling and shield tunneling methods are often employed with small intervals when the auxiliary lines approaching to a subway station. The tunnel cross sections formed by blasting are often extensive and various. When shield tunnel is being constructed, the impact of the two tunneling engineering is significant. A three dimensional numerical model is establishes to simulate the construction process of certain tunnel construction by using of the finite difference program FLAC 3D . The influence of tunnel construction on wall rock is analyzed, and the laws on how the post-constructed tunnel affects the displacement and stress distribution of the former constructed one are elaborated. The conclusive remarks can be a reference of the tunnel construction and other similar engineering projects. 1 INTRODUCTION In the practice of construction of auxiliary lines near the subway station, the methods of blast tunneling and shield tunneling are often adopted within a narrow area. And the blasting tunnel in this kind of project, with extensive and various cross sections, is often close to shield tunnels. Therefore, attention must be paid when the design and construct this kind of project are performed, by considering the interactive influence of the two constructions, which implies bigger risks (Liang 2007, Jiang et al 2011, Qiu 2011). At present, the researches of tunneling with small intervals in highway or railway constructions have achieved quite many fruits and experience (Bao 2011, Li 2013, Wei & Pang 2014). However, for a specific engineering, each tunnel has its own specificity in the process of construction due to the features of the project itself, such as the distance between the tunnels, the differences between cross sections, as well as the concerned geological conditions, the construction methods, etc. In this paper, FLAC3D finite differential program is employed and a three-dimensional model is established to calculate the displacement and the changes of stress state for a certain tunnel project. By analyzing its stability, some useful conclusions are reached.

ABSTRACT: For reducing boulder yield in bench blasting of an open pit mine, rock breaking mechanism in rock blasting is applied, while engineering geological survey, numerical simulation analysis and on-site tests are utilized. Through alteration of charge structure, detonate direction and adjustment of blasting sequence, fragmentation is obviously improved and the cost for secondary blasting, shoveling and loading are all reduced. 1 INTRODUCTION It is an important topic to lower boulder yield in drilling and blasting in mine. Rock blastability comprehensively reflects its own physical-mechanical properties as well as explosive and blasting process; natural rock mass contains numerous faults, joints, fractures and other structural surfaces, thus its strengthen depends on rock strength and strength of structural surface and is mainly controlled by the latter in more conditions. Therefore, most of fracture planes of rock are generated along structural surface inside the rock mass. Structural surface imposes stress concentration, reflection enhancement of stress wave, energy absorption, energy release, pitching-in, change of break line, etc. on blasting effect. It is commonly wished to search for the most proper explosive and blasting parameters under set ore rock properties in mine production, thus to reach the composition featuring the lowest total mining production cost. Therefore, the method for lowering boulder yield in blasting for fracture-developed mine is directly associated with economic and safety benefit of mine.

ABSTRACT: The starter dam of a tailings pond, adopted sectional construction, might cause differential settlement, which will bring bad impact on the dam stability during use later. First, the deformation rate of starter dam was monitored by INSAR technology for 14 hours, which demonstrated that the nonuniform deformation rate was within the permissible security range. Secondly, by means of numerical calculation, simulating the real conditions of sequence of sectional construction, studying the distribution and the change relationship of the starter dam deformation along with the construction steps, it was concluded that the numerical calculation results mostly coincided with the monitoring results on both the whole settlement and uneven settlement distribution of the starter dam. At last, considering the real situation of tailings pond in the later use, the stability of the starter dam was analyzed under the fluid-structure interaction. The results show that the starter dam could remain stable during construction and later use. 1 OVERVIEW Tailing pond, damming the valley mouth or compound, is used for storage of ore tailings or industrial waste, which is produced by metal and nonmetal mines after beneficiation. Tailing pond is a major hazard with high potential of man-made debris flow, once the dam breaks, it will cause great disaster follows by great losses. Operational tailing ponds are not only related to the mine's own safety and economic benefits, but also closely related to the lives and property of the downstream residents and their surrounding environment (Ma et al. 2010, Xie et al. 2009). The security and stability of starter Dam with Section Construction plays a vital role for the safe operation of tailing pond. Therefore, the starter tailing dam stability monitoring and analysis are of great significance.

ABSTRACT: The geological hazard and environmental problems induced by coalmine goafs have become one of important factors that impacting the safety and sustainable development of regions and enterprises in China. In order to prevent and reduce the mine earthquake induced by suddenly collapse of large scale coalmine goafs, the surface isolation grouting technology is put forward innovatively. Based on the introduction of the theory and feature of isolation grouting prevention and control technology, the thesis analyzed the smallest instability area of old coalmine goafs through statistical analyses and numerical simulation analyses, the 20,000 square meters goaf was selected as one isolation grouting unit. In addition, it gave concrete exposition in the aspects such as the drilling layout parameters, grouting material ratio, engineering quantity of isolation grouting, drilling and grouting construction process, case analyses, etc. The results show that the isolation grouting prevention and control selected as one isolation grouting unit with 20,000 square meters is with lower cost, and can effectively avoid or decrease the mine earthquake caused by suddenly collapse of large scale goafs, control or inhibit the goafs spontaneous combustion or ignition in some degree. So it is a kind of reference and promotion method in the prevention and control of coalmine goafs hazard. 1 INTRODUCTION The old coalmine goafs generally refer to the remained goafs after room and pillar method or roadway and pillar method mining. The features of the goafs are many irregular pillars remained, uncertain time of surface collapse, etc. The mine earthquake induced by sudden collapse of largescale golfs has become the increasing serious problem in Western China. For example, from the year 2004 to the year 2012, only for the mine earthquake level more than 2.0 grads, there are 76 mine earthquake accidents had happened in Yulin City. The typical cases are seen in Table 1 (Dong et al. 2005, Di et al. 2009). In the terms of old coalmine goafs prevention and control, many experts and scholars conducted a series of researches (Li & Yao 2004, Wang et al. 2007, Li et al. 2002), combining the many years' experience of Chinese Coal Research Institute (CCRI) (Zhang 2008, CCRI 2010, 2011, Wen 2011, 2013, Li et al. 2011, Liu et al. 2012), generally speaking, as for the old goafs with no buildings and structures on surface, the open stripe and reclamation control scheme is prior consideration adopted when old goafs were shallowly buried (less than 100 m).

ABSTRACT: Risk factors of buildings safety, taking a hotel as an example, induced by line 3 of Qingdao subway excavation are summarized based on detailed exploration and investigation of rock and soil mass properties underground, hydrological properties, tunnel excavation and support methods, building structure type and foundation form. Mechanism and development trend of various factors are studied under cavern. The characteristics and laws of influence factors are summarized. The degree of building damage and influence of various factors on building safety are predicted. Technical approach is studied to avoid the risk. Specific measures are proposed to control the risk. These results will provide a useful guidance for tunnel excavation of Qingdao and also in similar area. 1 INTRODUCTION Rock and soil mass surrounding a tunnel will be inevitably disturbed by tunnel excavation. The original equilibrium state of geotechnical body was destroyed. The original in situ stress will redistribute which leads to the subsidence and deformation of surface. Thereby, the safety of the existing buildings on the ground will be threatened. It should strictly control subsidence and deformation of the strata and the buildings on the ground for buildings safety when anomalies occur during tunnel excavation. Pre-recovery measures should be taken to control further damage to the buildings and ensure the structure safety when subsidence value and deformation value exceeds the allowable value. The practice shows that the grouting is one of the effective measures to reinforce strata, reduce strata subsidence and protect the existing buildings on the ground (Yuan 2010). Taking a hotel as an example, the subsidence value of the building foundation is predicted based on numerical simulation respectively, without grouting, grouting in weak strata and grouting in weak strata and within 1 m above, Grouting effect of weak strata is analyzed.

ABSTRACT: More and more anchoring failure of anchorage happens in the coalmine. Base on the structure and mechanical characteristics of prestressed single anchorage, reasons of anchor failure of single anchorage included hardness difference between anchorage clip and cable strand, diameter error of cable strand, strength and hardness of cable strand, limit distance and anchorage quality are analyzed. By site investigation, quality of cable support materials and construction quality were known. Measures for solution of anchorage failure were put forward, including controlling the quality of cable and anchor strictly, defining correct limit distance, making construction standardization and strengthening testing and standard construction. 1 INTRODUCTION It is being used more and more widely in coal industry, because of its good flexibility, convenient construction, large anchoring depth and high prestress of small borehole cable (Kang et al. 2009). Study on cable in coal industry is changing from anchoring length and prestress to some details, such as diffusion and loss of prestress (Kang et al. 2011). But still some questions in application of small borehole cable in coal industry, just like only focusing on the length and strength, overlooking matched components such as anchorage, plate and et al. Many situations include slip of anchorage and cable being sheared caused cable failure directly, which would cause roof accident on account of large area supporting unloading suddenly. Sliding of anchorage on cable can produce spark, which brings threat to the management of gas and coal dust. The industry has not yet attached great importance to anchoring reliability. Some engineer technicians thought that large surrounding pressure caused anchoring failure and anchorage unloading was safe, which was inconsistent with anchoring principle. The influencing factors of anchoring reliability are too much. This paper will discuss the main factors by analyzing the structure of anchorage and its compatibility with cable parameters, and put forward targeted technical measures.