In order to release the tension and shear effect of the superjacent rock strata movement during excavation in coal mine,protect the surface borehole case from fracturing fast and make a good use of the surface borehol...In order to release the tension and shear effect of the superjacent rock strata movement during excavation in coal mine,protect the surface borehole case from fracturing fast and make a good use of the surface borehole during goaf methane drawing,a common synthesis tension deformation fracture model was set up based on the synthesis tension effect of the rock strata,and the deformation rule of the surface borehole case with time and space was researched.The results suggest that,to reduce the deformation the surface borehole should be built between the boundary of the stope and the knee of subsidence curve.At the same time,a 3DEC simulation model and an engineering example were carried out to examine the rules of theoretical model.The result suggests that the model and the rules accord to the test and have good building and protection engineering application values to the surface borehole.展开更多
Dinggye lies in the middle part of the Himalayan Orogen. A lot of low angle extension detachment faults have been developed in Dinggye area and some of them make up the main body of the South Tibet Detachment System. ...Dinggye lies in the middle part of the Himalayan Orogen. A lot of low angle extension detachment faults have been developed in Dinggye area and some of them make up the main body of the South Tibet Detachment System. On the whole, the extension direction of all the detachment faults is perpendicular to the strike of the Himalayan Orogen. Each detachment fault has its distinct characteristics. Mylonite was extensively developed in the detachment faults and can be divided into a variety of types such as siliceous mylonite, felsic mylonite, granite mylonite, protomylonite, crystallization mylonite and so on. On the basis of our field survey works, these detachment faults can be classified according to their locations into three units listed as follows: (1) In the northern part of the study area, the detachment faults occur on large scale and in orbicular shape, and form the middle layer of the metamorphic core complexes. (2) In the southern part of the study area, the detachment faults occur in linear shape that is parallel to the Himalayan Orogen and has a stable attitude, and have undergone two phases of development. In the first phase, the Rouqiechun Group rocks were formed and make up the hanging wall, while in the second phase the Jiachun Group rocks were formed and make up the hanging wall. (3) In the southeastern part of the study area, the detachment faults strike nearly along southeast direction in a stable way and some of these detachment faults were distorted by the late-formed faults and folds. Furthermore, in the southwestern part of the study area, the ductile shear zones are parallel to the detachment faults.展开更多
A series of physical modelings in which a main roof is considered as a Kirchhoff plate supported or clammed by Winkler elastic foundation were performed to simulate the fracturing process of the main roof in longwall ...A series of physical modelings in which a main roof is considered as a Kirchhoff plate supported or clammed by Winkler elastic foundation were performed to simulate the fracturing process of the main roof in longwall mining. Based on these modelings spatial structures of the main roof after its fracture are described, blocks of the fractured main roof are classified and their behaviors are analyzed in this paper. Additionally, two stability indexes of the structures are defined, and the factors affecting stability of the structures with different boundaries and geometric conditions are discussed.展开更多
基金supports for this work provided by the NationalScience and Technology Major Project (No. 2011ZX05040-004)the National Great Research Foundation of China (No.2011CB201203)the National Natural Science Foundation of China(No. 50904034)
文摘In order to release the tension and shear effect of the superjacent rock strata movement during excavation in coal mine,protect the surface borehole case from fracturing fast and make a good use of the surface borehole during goaf methane drawing,a common synthesis tension deformation fracture model was set up based on the synthesis tension effect of the rock strata,and the deformation rule of the surface borehole case with time and space was researched.The results suggest that,to reduce the deformation the surface borehole should be built between the boundary of the stope and the knee of subsidence curve.At the same time,a 3DEC simulation model and an engineering example were carried out to examine the rules of theoretical model.The result suggests that the model and the rules accord to the test and have good building and protection engineering application values to the surface borehole.
基金supported by China Geological Survev's regional geological survey program(No.200013000145)in the Dinggve area(H45C004003)of the Qinghai-Tibet Plateau on a scale of 1:250 000
文摘Dinggye lies in the middle part of the Himalayan Orogen. A lot of low angle extension detachment faults have been developed in Dinggye area and some of them make up the main body of the South Tibet Detachment System. On the whole, the extension direction of all the detachment faults is perpendicular to the strike of the Himalayan Orogen. Each detachment fault has its distinct characteristics. Mylonite was extensively developed in the detachment faults and can be divided into a variety of types such as siliceous mylonite, felsic mylonite, granite mylonite, protomylonite, crystallization mylonite and so on. On the basis of our field survey works, these detachment faults can be classified according to their locations into three units listed as follows: (1) In the northern part of the study area, the detachment faults occur on large scale and in orbicular shape, and form the middle layer of the metamorphic core complexes. (2) In the southern part of the study area, the detachment faults occur in linear shape that is parallel to the Himalayan Orogen and has a stable attitude, and have undergone two phases of development. In the first phase, the Rouqiechun Group rocks were formed and make up the hanging wall, while in the second phase the Jiachun Group rocks were formed and make up the hanging wall. (3) In the southeastern part of the study area, the detachment faults strike nearly along southeast direction in a stable way and some of these detachment faults were distorted by the late-formed faults and folds. Furthermore, in the southwestern part of the study area, the ductile shear zones are parallel to the detachment faults.
文摘A series of physical modelings in which a main roof is considered as a Kirchhoff plate supported or clammed by Winkler elastic foundation were performed to simulate the fracturing process of the main roof in longwall mining. Based on these modelings spatial structures of the main roof after its fracture are described, blocks of the fractured main roof are classified and their behaviors are analyzed in this paper. Additionally, two stability indexes of the structures are defined, and the factors affecting stability of the structures with different boundaries and geometric conditions are discussed.
