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Editor Work1996 Vol. 4, No. 2
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1996, 4(2): 1-6.
Abstract
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Using the basic principles of stereographic projection, block theory and rock mechanics, this paper has tried to find a simple and easy method for datermination of maximum safe cut angle for design and bolt scheme.
Using the basic principles of stereographic projection, block theory and rock mechanics, this paper has tried to find a simple and easy method for datermination of maximum safe cut angle for design and bolt scheme.
1996, 4(2): 7-13.
In this paper, a study on selection of mechanical indexes for rock-mass quality classifacation at a damsite of a hydroelectric power station permites us to explain the meaning of rock-mass quality classifacation and discuss, mechanical index selection and establishment of the relationship between the mechanical parameters.
In this paper, a study on selection of mechanical indexes for rock-mass quality classifacation at a damsite of a hydroelectric power station permites us to explain the meaning of rock-mass quality classifacation and discuss, mechanical index selection and establishment of the relationship between the mechanical parameters.
1996, 4(2): 14-18.
The Zhexi Reservoir was impounded from Feb. 15 1961 by closinggate. Up to March of 1995 it was operating 34 years. Because of bar sedimentation the water level rises in the upstream in flood season and hence the losses from inundation in its surroundings and tail of thereservoir increase and the transport is influenced. Thus it must betreated in time. From geological investigation and observation data of the bar sedimentation, an analysis of the source for silt is made audits controlling measures are discussed in the paper.
The Zhexi Reservoir was impounded from Feb. 15 1961 by closinggate. Up to March of 1995 it was operating 34 years. Because of bar sedimentation the water level rises in the upstream in flood season and hence the losses from inundation in its surroundings and tail of thereservoir increase and the transport is influenced. Thus it must betreated in time. From geological investigation and observation data of the bar sedimentation, an analysis of the source for silt is made audits controlling measures are discussed in the paper.
Marble is widely distributed in Yuanlang area of Hong Kong. The mechanical properties of the marble influence directly the safety of construction in the area. We have used ultrasonic detection technique, uniaxial compression test, and observation of thin section of the rock under microscope for understanding the internal structural change and mechanical properties of the marble. The obtained result shows that the mechanical properties of the marble in the area change significantly. In general, the dense black marble shows higher ultrasonic velocity, higher compression strength, and brittleness.Its P wave velocity ranges in 6. 2～6. 5 km. s-1, S wave velocity in 3. 0～0. 60 km.s-1, and its compressionstrength ranges in 88～66 MPa. But the coarse rained white or greymarble has its largely varied ultrasonic velocity, lower compression strength, and ductility. Its P wave velocity ranges in 4. 2～6. 9 km. s-1, Swave velocity in 2. 4-3. 20km. s-1, and compression strength in 52～63 MPa. The P wave is inversely proportional to crack density. The compressions trength is linearly inversely proportional to crack density. But the slope of curve for the brittle marble is higher than that for theductile marble by many times. The internal microscopic structures of themarble, such as cracks and grain size, are the main factors affectingits mechanical properties.
Marble is widely distributed in Yuanlang area of Hong Kong. The mechanical properties of the marble influence directly the safety of construction in the area. We have used ultrasonic detection technique, uniaxial compression test, and observation of thin section of the rock under microscope for understanding the internal structural change and mechanical properties of the marble. The obtained result shows that the mechanical properties of the marble in the area change significantly. In general, the dense black marble shows higher ultrasonic velocity, higher compression strength, and brittleness.Its P wave velocity ranges in 6. 2～6. 5 km. s-1, S wave velocity in 3. 0～0. 60 km.s-1, and its compressionstrength ranges in 88～66 MPa. But the coarse rained white or greymarble has its largely varied ultrasonic velocity, lower compression strength, and ductility. Its P wave velocity ranges in 4. 2～6. 9 km. s-1, Swave velocity in 2. 4-3. 20km. s-1, and compression strength in 52～63 MPa. The P wave is inversely proportional to crack density. The compressions trength is linearly inversely proportional to crack density. But the slope of curve for the brittle marble is higher than that for theductile marble by many times. The internal microscopic structures of themarble, such as cracks and grain size, are the main factors affectingits mechanical properties.
1996, 4(2): 24-30.
In this paper the mining effect caused by undergroud mining and deformation characteristics of the land subsidence basin are evaluated by using numerical simulation method. The maximum land subsidence caused by the first-term excavation is less than 700 mm, the maximum subsidence caused by the second-term deep excavation will not be larger than 995mm. If back-filling in the stopes is used, the maximum subsidence will be reduced by 55%. Because the relative defferential subsidence deformation of the land surface is less than 1mm. m-1, and there exist two overlying impermeable clay layers (thickness from 3～5 m to 5～7 m, respectively), such deformation of the land surface will not destroy the continuity of clay layers and not provide any path for surface water (seawater) to harm the safety of the mine.
In this paper the mining effect caused by undergroud mining and deformation characteristics of the land subsidence basin are evaluated by using numerical simulation method. The maximum land subsidence caused by the first-term excavation is less than 700 mm, the maximum subsidence caused by the second-term deep excavation will not be larger than 995mm. If back-filling in the stopes is used, the maximum subsidence will be reduced by 55%. Because the relative defferential subsidence deformation of the land surface is less than 1mm. m-1, and there exist two overlying impermeable clay layers (thickness from 3～5 m to 5～7 m, respectively), such deformation of the land surface will not destroy the continuity of clay layers and not provide any path for surface water (seawater) to harm the safety of the mine.
1996, 4(2): 31-35.
The main cause for the surface deformation of Fushun Petroleum Factory No. 1 area is the surface bench mining in the western pit of the surface mine. The mining led to slope failure, deformation, and surface subsidence in the factorys southern edge.Meanwhile, this activates other factors and accelerated the development of the ground fissure and deformation.
The main cause for the surface deformation of Fushun Petroleum Factory No. 1 area is the surface bench mining in the western pit of the surface mine. The mining led to slope failure, deformation, and surface subsidence in the factorys southern edge.Meanwhile, this activates other factors and accelerated the development of the ground fissure and deformation.
1996, 4(2): 36-43.
Joint Roughness Coefficient (JRC ) is an equivalent index which describes mechanical effect of rock joint surface angle of ascent. In this paper, we firstly determined the physical meaning of JRC straight edge based on the mechanism study of mechanical effect of the angle of ascent and then we affirmed its rationality through the comparative analysis of the undulation amplitude of rock joint surface and the roughness amplitude of metallic surface. After that, we gave a mathematical formula and its computer program for JRC modified straight edge which contain scale effect of joint roughness coefficient.At the last I the rationality and availability of JRC modified straight edge were tested by practical example.
Joint Roughness Coefficient (JRC ) is an equivalent index which describes mechanical effect of rock joint surface angle of ascent. In this paper, we firstly determined the physical meaning of JRC straight edge based on the mechanism study of mechanical effect of the angle of ascent and then we affirmed its rationality through the comparative analysis of the undulation amplitude of rock joint surface and the roughness amplitude of metallic surface. After that, we gave a mathematical formula and its computer program for JRC modified straight edge which contain scale effect of joint roughness coefficient.At the last I the rationality and availability of JRC modified straight edge were tested by practical example.
1996, 4(2): 44-50.
The expert system for interlayer shear zone is a practical expert system which studies and evaluates specially engineering-geological problems of interlayer shear zone. The field knowledge model constructed for studying the system is introduced in this paper.This knowledge model is constructed on the basis of summarizing and concluding some knowledge and experience of three well-known experts in this field and provides a base for expressing and inference of expert system knowledge.
The expert system for interlayer shear zone is a practical expert system which studies and evaluates specially engineering-geological problems of interlayer shear zone. The field knowledge model constructed for studying the system is introduced in this paper.This knowledge model is constructed on the basis of summarizing and concluding some knowledge and experience of three well-known experts in this field and provides a base for expressing and inference of expert system knowledge.
1996, 4(2): 51-56.
Ground Penetrating radar (GPR) survey is one of the geophysical exploration methods and is widely used in engineering geology. This paper describe the GPR survey principle and working method. Some results of GPR application in engineering geology are present in the paper.
Ground Penetrating radar (GPR) survey is one of the geophysical exploration methods and is widely used in engineering geology. This paper describe the GPR survey principle and working method. Some results of GPR application in engineering geology are present in the paper.
1996, 4(2): 57-62.
On the basis of distribution of the dillative politic rock and its engineering characteristics in the construction area for directing the Huanghe River into northwestern Shanxi Province, the methods are proposed for eptimizing tunnel line arrangement and engineering control for tunnel construction in accordance with the dilative rocks special distribution. It is important and has reference value for the underground work in the dilative rock area.
On the basis of distribution of the dillative politic rock and its engineering characteristics in the construction area for directing the Huanghe River into northwestern Shanxi Province, the methods are proposed for eptimizing tunnel line arrangement and engineering control for tunnel construction in accordance with the dilative rocks special distribution. It is important and has reference value for the underground work in the dilative rock area.
1996, 4(2): 63-68.
According to Mohr-Coulomb yield condition and non-related flowing rule in consideration of the crustal stress field and engineering characteristics of underground gate,we propose a method for determing the plastic state of sorrounding rocks of gate. By FEM analysis of sourrounding rocks for the unsupported gate and bolt-supported gate,we got the result that to support the gate by bolt immediatly after digging the gate, it can improve the stiffness and strength equivalently of the surrounding rock.
According to Mohr-Coulomb yield condition and non-related flowing rule in consideration of the crustal stress field and engineering characteristics of underground gate,we propose a method for determing the plastic state of sorrounding rocks of gate. By FEM analysis of sourrounding rocks for the unsupported gate and bolt-supported gate,we got the result that to support the gate by bolt immediatly after digging the gate, it can improve the stiffness and strength equivalently of the surrounding rock.
1996, 4(2): 69-74.
Based on the controlling effect of rock mass structure on the permeability of rock mass, the percolation media of rock mass are divided into four types, i. e. porous,quasi-porous, planar flow discontinuous and vein flow discontinuous media. The complicated permeability of rock mass I involving inhomogeneous, anisotropic. unsaturated behaviour as well as the coupling between hydraulic conductivity and deformation are discussed. The technical routines for the percolation analysis of rock mass are alsohere.
Based on the controlling effect of rock mass structure on the permeability of rock mass, the percolation media of rock mass are divided into four types, i. e. porous,quasi-porous, planar flow discontinuous and vein flow discontinuous media. The complicated permeability of rock mass I involving inhomogeneous, anisotropic. unsaturated behaviour as well as the coupling between hydraulic conductivity and deformation are discussed. The technical routines for the percolation analysis of rock mass are alsohere.
1996, 4(2): 75-80.
The relation between rupture of auxiliary shaft and hydrogeological conditions of bottom aquifer in Quaternary system is discussed from hydrodynamic and hydrochemical conditions in Kongzhuang colliery of Datun in the paper. The influences of the change of hydrogeological conditions on forcing state and strength characteristic of auxiliary shaft,bottom aquifer, and its surrounding rock-soil mass are analyzed in detail. An importance of hydrodynamic change in analysis of outer stress environment for the shaft and dormage from hydrochemical corrosion which has effect on strength of shaft lining concrete are first put forward.
The relation between rupture of auxiliary shaft and hydrogeological conditions of bottom aquifer in Quaternary system is discussed from hydrodynamic and hydrochemical conditions in Kongzhuang colliery of Datun in the paper. The influences of the change of hydrogeological conditions on forcing state and strength characteristic of auxiliary shaft,bottom aquifer, and its surrounding rock-soil mass are analyzed in detail. An importance of hydrodynamic change in analysis of outer stress environment for the shaft and dormage from hydrochemical corrosion which has effect on strength of shaft lining concrete are first put forward.
1996, 4(2): 81-86.
Carbonate rocks are widely distributed in Zhongtiaoshan area, where annual precipitation is 740 mm, mean annual temperature is 14℃. The climatic conditions and multiple tectonic movements controlled anddetermined the development of karst, geomorphologic landscape, and theoccurrence and transportation of ground water through karst. Here thepercolation becomes an outstanding engineering geological problem inwater conservancy and hydropower construction and has a certaininfluence on dam sitting.
Carbonate rocks are widely distributed in Zhongtiaoshan area, where annual precipitation is 740 mm, mean annual temperature is 14℃. The climatic conditions and multiple tectonic movements controlled anddetermined the development of karst, geomorphologic landscape, and theoccurrence and transportation of ground water through karst. Here thepercolation becomes an outstanding engineering geological problem inwater conservancy and hydropower construction and has a certaininfluence on dam sitting.
1996, 4(2): 87-96.
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