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您的检索式：关键字=stress unloading
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| 1 | THE PRECURSOR OF INSTABILITY FOR NONLINEAR SYSTEMS AND ITS APPLICATION TO EARTHQUAKE PREDICTION显示文摘By analysing the instability process of various nonlinear systems, we conclude that their instability precursors are the continual heightening of the response rate or response ratio.Applying this theory to earthquake prediction, we adopt the periodical change of the stress in crust caused by the tide-generating force as the loading and unloading. If we can measure the ratio of the response (such as crust deformation, gravity and seismicity) during the loading period to that during the unloading period, this parameter must contain some characteristic information about the seismogenic process.With nine earthquakes (M≥7) data that occurred in Chinese mainland during 1970-1988, we take the sum of square root o?energy of small earthquakes, which is called the released strain by Benioff, as the response to the tidal loading and unloading. We find that the response ratios of seven earthquakes increase obviously before the main earthquakes. | 尹祥础 尹灿 | 1991 | Science China Chemistry1991，34，8： | 19 |
| 2 | An approach to measure infill matric suction of irregular infilled rock joints under constant normal stiffness shearing显示文摘Rock joints infilled with sediments can strongly influence the strength of rock mass. As infilled joints often exist under unsaturated condition, this study investigated the influence of matric suction of infill on the overall joint shear strength. A novel technique that allows direct measurement of matric suction of infill using high capacity tensiometers(HCTs) during direct shear of infilled joints under constant normal stiffness(CNS) is described. The CNS apparatus was modified to accommodate the HCT and the procedure is explained in detail. Joint specimens were simulated by gypsum plaster using threedimensional(3D) printed surface moulds, and filled with kaolin and sand mixture prepared at different water contents. Shear behaviours of both planar infilled joints and rough joints having joint roughness coefficients(JRCs) of 8-10 and 18-20 with the ratios of infill thickness to asperity height(t/a)equal to 0.5 were investigated. Matric suction shows predominantly unimodal behaviour during shearing of both planar and rough joints, which is closely associated with the variation of unloading rate and volumetric changes of the infill material. As expected, two-peak behaviour was observed for the rough joints and both peaks increased with the increase of infill matric suction. The results suggest that the contribution of matric suction of infill on the joint peak normalised shear stress is relatively independent of the joint roughness. | Libin Gong Ana Heitor Buddhima Indraratna | 2018 | Journal of Rock Mechanics and Geotechnical Engineering2018，10，4： | 1 |
| 3 | Effects of the Nepal M_S8. 1 Earthquake in 2015 on Seismic Activity in the Qinghai-Tibetan Plateau显示文摘We obtained the displacement and deformation caused by the 2015 Nepal MS8. 1 earthquake adopting the finite element method,and analyzed the displacement and deformation characteristics and effect of three large earthquakes on seismic activity in the Qinghai-Tibetan block. Our primary results suggest southward movement of the QinghaiTibetan block is caused by a large earthquake occurring on thrust fault in the Himalayan zone,the displacement direction is reverse to the background displacement. The occurrence of these large earthquakes will result in stress unloading and earthquake activity will be weakened in stress unloading areas. Through the simulation results,we can detect the distribution area of stress loading and unloading caused by large earthquakes.Simultaneously,it provides a fundamental evidence for determination of earthquake activity trend. | CHENG Guoliang ZHANG Yuansheng WEI Congxin | 2019 | Earthquake Research in China2019，33，3： | 0 |
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