The primary purpose of underground gas storages is to provide gas for seasonal consumptions or strategic reserve.The periodical operations of gas injection and extraction lead to cyclic loading on the walls and surrou...The primary purpose of underground gas storages is to provide gas for seasonal consumptions or strategic reserve.The periodical operations of gas injection and extraction lead to cyclic loading on the walls and surrounding rocks of gas storages.To investigate the mechanical behaviors of different host rocks in bedded salt deposit,laboratory experiments were conducted on the samples of rock salt,thenardite,glauberite and gypsum.The mechanical properties of rock samples under monotonic and cyclic loadings were studied.Testing results show that,under monotonic loading,the uniaxial compressive stress(UCS) of glauberite is the largest(17.3 MPa),while that of rock salt is the smallest(14.0 MPa).The UCSs of thenardite and gypsum are 16.3 and 14.6 MPa,respectively.The maximum strain at the peak strength of rock salt(halite) is much greater than those of the other three rocks.The elastic moduli of halite,thenardite,glauberite and gypsum are 3.0,4.2,5.1 and 6.8 GPa,respectively.Under cyclic loading,the peak strengths of the rock specimens are deteriorated except for rock salt.The peak strengths of thenardite,glauberite and gypsum decrease by 33.7%,19.1% and 35.5%,respectively;and the strains of the three rocks at the peak strengths are almost the same.However,the strain of rock salt at the peak strength increases by 1.98%,twice more than that under monotonic loading.Under monotonic loading,deformation of the tested rock salt,thenardite and glauberite shows in an elastoplastic style.However,it changes to a ductile style under cyclic loading.Brittle deformation and failure are only observed for gypsum.The results should be helpful for engineering design and operation of gas storage in bedded salt deposit.展开更多
Hot dry rock(HDR) geothermal energy,almost inexhaustible green energy,was first put forward in the 1970s.The development and testing of HDR geothermal energy are well reported in USA,Japan,UK,France and other countrie...Hot dry rock(HDR) geothermal energy,almost inexhaustible green energy,was first put forward in the 1970s.The development and testing of HDR geothermal energy are well reported in USA,Japan,UK,France and other countries or regions.In this paper,the geological characters of Yangbajing basin were first analyzed,including the continental dynamic environments to form HDR geothermal fields in Tibet,the tectonic characteristics of south slope of Nyainqêntanglha and Dangxiong-Yangbajing basin,and the in-situ stresses based on the investigations conducted,and then the site-specific mining scheme of HDR geothermal resources was proposed.For the potential development of HDR geothermal energy,a series of experiments were conducted on large-scale granite samples,200 mm in diameter and 400 mm in length,at high temperature and high triaxial pressure for cutting fragmentation and borehole stability.For the borehole stability test,a hole of 40 mm in diameter and 400 mm in length was aforehand drilled in the prepared intact granite sample.The results indicate that the cutting velocity obviously increases with temperature when bit pressure is over a certain value,while the unit rock-breaking energy consumption decreases and the rock-breaking efficiency increases with temperature at the triaxial pressure of 100 MPa.The critical temperature and pressure that can result in intensive damage to granite are 400-500 ℃ and 100-125 MPa,respectively.展开更多
Rock mass mechanics can be classified into engineering rock mass mechanics and disaster rock mass mechanics based on science and application.Their conception,object,scientific essence and application were elaborated.T...Rock mass mechanics can be classified into engineering rock mass mechanics and disaster rock mass mechanics based on science and application.Their conception,object,scientific essence and application were elaborated.The connotation,studying method and theoretical framework of disaster rock mass mechanics were described.Disaster rock mass mechanics is a strongly nonlinear discipline which is a strong tool to study natural and artificially-induced disasters.The rock mass system where disasters happen exhibits extremely spatial-temporal nonlinearity in the critically unstable state.Hence,the potentially effective prediction and forecasting of disasters depends on statistical analysis of highly probable events.The direction of efforts for predicting and forecasting disasters could be to find the quantitative or semi-quantitative relationship between physical and biological information and instability of rock mass system.展开更多
The failure of rocks is a complicated process as the mechanical properties of the rock are governed by loading history and cumulative ruptures.The geometric aspects of fractures,such as the size and shape of the fract...The failure of rocks is a complicated process as the mechanical properties of the rock are governed by loading history and cumulative ruptures.The geometric aspects of fractures,such as the size and shape of the fractures,the spatial distribution of the fracture networks,and the relations among these aspects also depend on the loads acting on rock mass.In general,the fractures are randomly generated in space which is difficult to be described using mathematical methods.In this paper,the failure processes of rock have been analyzed using the percolation theory.The results indicate that the failure process of rock is a transition from a stable state to an unstable state.This phenomenon is essentially consistent with the phase transition in the percolation theory.Based on this consistency,a theoretical model of percolation for earthquake prediction is proposed.A large number of seismic data provided strong evidence in support of the reliability and applicability of this model.展开更多
基金Supported by the Program for New Century Excellent Talents in University of China (NCET-07-0594)the National Natural Science Foundation of China (50874078 and 50804033)the Special Support for National Excellent Ph.D.Thesis (200959)
文摘The primary purpose of underground gas storages is to provide gas for seasonal consumptions or strategic reserve.The periodical operations of gas injection and extraction lead to cyclic loading on the walls and surrounding rocks of gas storages.To investigate the mechanical behaviors of different host rocks in bedded salt deposit,laboratory experiments were conducted on the samples of rock salt,thenardite,glauberite and gypsum.The mechanical properties of rock samples under monotonic and cyclic loadings were studied.Testing results show that,under monotonic loading,the uniaxial compressive stress(UCS) of glauberite is the largest(17.3 MPa),while that of rock salt is the smallest(14.0 MPa).The UCSs of thenardite and gypsum are 16.3 and 14.6 MPa,respectively.The maximum strain at the peak strength of rock salt(halite) is much greater than those of the other three rocks.The elastic moduli of halite,thenardite,glauberite and gypsum are 3.0,4.2,5.1 and 6.8 GPa,respectively.Under cyclic loading,the peak strengths of the rock specimens are deteriorated except for rock salt.The peak strengths of thenardite,glauberite and gypsum decrease by 33.7%,19.1% and 35.5%,respectively;and the strains of the three rocks at the peak strengths are almost the same.However,the strain of rock salt at the peak strength increases by 1.98%,twice more than that under monotonic loading.Under monotonic loading,deformation of the tested rock salt,thenardite and glauberite shows in an elastoplastic style.However,it changes to a ductile style under cyclic loading.Brittle deformation and failure are only observed for gypsum.The results should be helpful for engineering design and operation of gas storage in bedded salt deposit.
文摘Hot dry rock(HDR) geothermal energy,almost inexhaustible green energy,was first put forward in the 1970s.The development and testing of HDR geothermal energy are well reported in USA,Japan,UK,France and other countries or regions.In this paper,the geological characters of Yangbajing basin were first analyzed,including the continental dynamic environments to form HDR geothermal fields in Tibet,the tectonic characteristics of south slope of Nyainqêntanglha and Dangxiong-Yangbajing basin,and the in-situ stresses based on the investigations conducted,and then the site-specific mining scheme of HDR geothermal resources was proposed.For the potential development of HDR geothermal energy,a series of experiments were conducted on large-scale granite samples,200 mm in diameter and 400 mm in length,at high temperature and high triaxial pressure for cutting fragmentation and borehole stability.For the borehole stability test,a hole of 40 mm in diameter and 400 mm in length was aforehand drilled in the prepared intact granite sample.The results indicate that the cutting velocity obviously increases with temperature when bit pressure is over a certain value,while the unit rock-breaking energy consumption decreases and the rock-breaking efficiency increases with temperature at the triaxial pressure of 100 MPa.The critical temperature and pressure that can result in intensive damage to granite are 400-500 ℃ and 100-125 MPa,respectively.
基金supported by the National Natural Science Foundation of China(Grant No.52122405)Shanxi major research program for science and technology(Grant No.202101060301024).
文摘Rock mass mechanics can be classified into engineering rock mass mechanics and disaster rock mass mechanics based on science and application.Their conception,object,scientific essence and application were elaborated.The connotation,studying method and theoretical framework of disaster rock mass mechanics were described.Disaster rock mass mechanics is a strongly nonlinear discipline which is a strong tool to study natural and artificially-induced disasters.The rock mass system where disasters happen exhibits extremely spatial-temporal nonlinearity in the critically unstable state.Hence,the potentially effective prediction and forecasting of disasters depends on statistical analysis of highly probable events.The direction of efforts for predicting and forecasting disasters could be to find the quantitative or semi-quantitative relationship between physical and biological information and instability of rock mass system.
基金financial support was provided by National Natural Science Foundation of China(Grant No.52122405)provided by Shanxi major research program for science and technology(Grant No.202101060301024).
文摘The failure of rocks is a complicated process as the mechanical properties of the rock are governed by loading history and cumulative ruptures.The geometric aspects of fractures,such as the size and shape of the fractures,the spatial distribution of the fracture networks,and the relations among these aspects also depend on the loads acting on rock mass.In general,the fractures are randomly generated in space which is difficult to be described using mathematical methods.In this paper,the failure processes of rock have been analyzed using the percolation theory.The results indicate that the failure process of rock is a transition from a stable state to an unstable state.This phenomenon is essentially consistent with the phase transition in the percolation theory.Based on this consistency,a theoretical model of percolation for earthquake prediction is proposed.A large number of seismic data provided strong evidence in support of the reliability and applicability of this model.
