... conclusions were drawn: a) If the sphericity of the earth is taken into account, it is possible to explain why the horizontal stress is larger than the vertical stress near the ground surface. In other words, the large horizontal stress is due to gravity not due to presumed tectonic forces resulting from...

... by the pressurization of the Fracture-free segment of the hole by pumping in water. The pressure is raised until the rock surrounding the hole fails in tension at a critical pressure. In a vertical test hole the hydrofrac is expected to be vertical and perpendicular to the minimum horizontal stress. Hubbert and Willis...

... in the underground facilities near the rock surface. Horizontal stresses can be utilized in stabilizing rock caverns and may then allow wide caverns to be excavated. Hence the stress measurements were also conducted in the P-Hamppi project with hydraulic fracturing method. This paper describes how the results were...

... the stability of underground openings are also presented. For instance, a wide opening can be excavated in a rock mass where the horizontal stresses are high enough. In a case of extremely high horizontal stresses, the stability of the roof could be improved by increasing the width of the opening. The basic...

... condition of high anisotropy, in other words, where the ratio of the maximum and the minimum horizontal stresses is large. Among the seven tested in situ stress conditions, the occurrence of an earthquake under the stress condition at the time of forebulge in front of the ice cover is found to produce...

... strain changes observed during in situ pressure test plotted against angular position around the borehole of measuring gauge. Estimating the Horizontal Stress Direction To investigate the variation in elastic modulus further, a single parameter representation of the local state of stress is helpful...

... horizontal stress Symposium stress measurement Upstream Oil & Gas Raasakka Tampere excavation Reservoir Characterization in-situ stress tampere rantatunneli highway tunnel project displacement Finland Johansson Rock stress in-situ rock stress international symposium santalahti tunnel...

... to change with time in order to maintain equilibrium in the Earth's crust. structural geology Stephansson reservoir geomechanics orientation information borehole Upstream Oil & Gas final rock stress model stress data stress measurement topography horizontal stress determination...

... to the jointing geometry since the sufficiently high normal stress will prevent the rock block from falling even the geometry is not favourable. In some situations the high horizontal stress plays a crucial role in maintaining stability of tunnels and caverns, which is particularly true for underground openings...

... Modeling & Simulation steel strand roadway metals & mining mudstone horizontal stress setup entry Reservoir Characterization multidimensional control stress measurement vertical stress cable truss Thickness coalside Rock stress span setup entry principal stress Rock Stress...

...; the increasing rate of horizontal stresses is larger than that of vertical stress in shallow sites, and gradually decrease as the depth increases. 1 INTRODUCTION Coal measures are extremely complicated geological bodies. When compared with other geological materials, they have two distinct characteristics...

... will hinder the construction program and add the construction cost. Therefore, basing on the mechanics analysis of linear elastic rock, the formula is established among the maximum and minimum horizontal stress with the tectonic stress coefficient, considering that horizontal principal stress is made up...

.... reservoir geomechanics orientation minimum principal stress metals & mining Reservoir Characterization Upstream Oil & Gas Kailuan mining area horizontal stress China syncline Engineering situ stress horizontal principal stress maximum horizontal principal stress geological structure...

... measurement result horizontal stress stress measurement tectonic stress footwall Earthquake Significance yingxiu-beichuan fault Wenchuan Earthquake Upstream Oil & Gas borehole aftershock great earthquake principal stress in-situ stress measurement Rock Stress and Earthquakes Xie (ed.) ©...

... capacity of storing initial geostatic stress. Large in situ horizontal stresses are kept in intact gneiss, with unaxial strength more than 45MPa and overburden more than 200 m. The large subhorizontal in situ stress mainly plays the role of σ2 during tunnel excavations in the section of gneiss with severe...

... the results from in-situ stress measurement. Zhu Huanchun andTao Zhenyu summarized the features of maximal and minimal horizontal stress variation with depth in the world. Brown obtained the ratio of vertical and horizontal average stress to vertical in-situ stress and its variation with depth. Mary Lou...

... with expected effects, and controlled the floor heave effectively. Keywords: Soft rock roadway floor heave deformation mechanism horizontal stress swelling soaking effect 1 INTRODUCTION When the excavation of roadway has been advanced, the balance of in-situ stress situation of rock mass was destroyed, which...

... ABSTRACT: A hybrid method for constraining all three principal in situ stresses and their directions around vertical boreholes at great depths is described. It involves hydraulic fracturing tests for estimating the minimum horizontal stress and its direction. The vertical stress is computed...

... limestone aquifer numerical simulation investigation aquifer water inrush Drilling principal stress Upstream Oil & Gas stress field mining deep mining horizontal stress stress measurement vertical stress Rock Stress and Earthquakes Xie (ed.) © 2010 Taylor & Francis Group, London, ISBN...

... horizontal stress in-situ stress principal stress Northeast Sichuan Sichuan inversion fracture Rock Stress and Earthquakes Xie (ed.) © 2010 Taylor & Francis Group, London, ISBN 978-0-415-60165-8 Inversion of marine in-situ stress of northeast Sichuan and its influence on horizontal well completion...