1995 Vol. 3, No. 1
1995, 3(1): 1-9.
The Wuluwati Hydropower Station on Kalakashi River in Xinjiang is located in an area with recent high active tectonic movement.The field evidence shows that fault F12 at the dam site exhibited multiphase activity up to the late Pleistocene,and faulting occurred on the North Shimen fault in the neighboring area in the Quaternary.We analysed the samples of fault materials collected along the faults at dam site and its surroundings by means of analysis of microstructures,quartz surface textures and TL dating. The results indicate that the upper time limit of the last faulting is about 30 and 20ka BP along the fault F12 and North Shimen fault,respectively,while the F30 and Shimen fault exhibited actitities by the Late Pleistocene.The structural model experiments based on distribution of the regional faults and stress field predict that stress concentration segment is located in an area far from the dam site. The dam area is a relatively stable segment.
The Wuluwati Hydropower Station on Kalakashi River in Xinjiang is located in an area with recent high active tectonic movement.The field evidence shows that fault F12 at the dam site exhibited multiphase activity up to the late Pleistocene,and faulting occurred on the North Shimen fault in the neighboring area in the Quaternary.We analysed the samples of fault materials collected along the faults at dam site and its surroundings by means of analysis of microstructures,quartz surface textures and TL dating. The results indicate that the upper time limit of the last faulting is about 30 and 20ka BP along the fault F12 and North Shimen fault,respectively,while the F30 and Shimen fault exhibited actitities by the Late Pleistocene.The structural model experiments based on distribution of the regional faults and stress field predict that stress concentration segment is located in an area far from the dam site. The dam area is a relatively stable segment.
1995, 3(1): 10-20.
From the detailed field investigation and comprehensive study includING X─ray diffraction analysis of muddy materials,chemical composition study of the soft intercalation, composition and characteristics of different sand─gravel materials , especially the microscopic structure and material source of the weak and soft zone at main pier site of Ningbo Bridge, an emphasis is made on the problem of genetic mechanism of the zone.It is revealed that this zone is composed of three parts or layers in structure indicating three types of evolutional processes of the zone or material sources. The research has practical significance in bridge design and constructions.
From the detailed field investigation and comprehensive study includING X─ray diffraction analysis of muddy materials,chemical composition study of the soft intercalation, composition and characteristics of different sand─gravel materials , especially the microscopic structure and material source of the weak and soft zone at main pier site of Ningbo Bridge, an emphasis is made on the problem of genetic mechanism of the zone.It is revealed that this zone is composed of three parts or layers in structure indicating three types of evolutional processes of the zone or material sources. The research has practical significance in bridge design and constructions.
1995, 3(1): 21-27.
Using the techniques of geomechanical mechanism simulation of resemble material,the tectonic gravity spreading mechanism of Xian ground fissures is reproduced and testified in this paper.Some important conclusions,such as the tectonic gravity spreading mechanism is the essential reason for the ground fissures,the engineering buildings can be safely planned if only keeping a certain distance from the ground fissures,the maximum depth of the around fissures extend is likely at the upper-middle part of Paleogene deposits,etc. are drawn out. The reason for the abnormal land subsidence is revealed preliminarily. The results has obvious theoretical significance and social-economic benefit.
Using the techniques of geomechanical mechanism simulation of resemble material,the tectonic gravity spreading mechanism of Xian ground fissures is reproduced and testified in this paper.Some important conclusions,such as the tectonic gravity spreading mechanism is the essential reason for the ground fissures,the engineering buildings can be safely planned if only keeping a certain distance from the ground fissures,the maximum depth of the around fissures extend is likely at the upper-middle part of Paleogene deposits,etc. are drawn out. The reason for the abnormal land subsidence is revealed preliminarily. The results has obvious theoretical significance and social-economic benefit.
1995, 3(1): 28-34.
In this paper the hydro-engineering geological conditions caused tunnel collapse and water gush,the prediction methods before and at construction steps and its importnt economic benefit are discussed from some existing examples. Five principles for improving prediction coincidence ratio are put forward.
In this paper the hydro-engineering geological conditions caused tunnel collapse and water gush,the prediction methods before and at construction steps and its importnt economic benefit are discussed from some existing examples. Five principles for improving prediction coincidence ratio are put forward.
1995, 3(1): 35-44.
A cusp catastrophe model is constructed for the strike-slip fault earthquake, a necessary criterion for judgement of sufficient mechanical earthquake and a simple expression of released energy by earthuake are presented. Based on the catastrophe theory analysis,a new assumption, simply called theory on induced earthquake by fault zone weakening and rockmass softening, is sugested reasonably explaining the relation between reservoir-induced earthquake and rock types,structures,water level,and the characteristic of b value of reservoir-induced earthguake sequence.We have a clear knowledge of reservoir-inuced earthquake mechanism from this paper discussion
A cusp catastrophe model is constructed for the strike-slip fault earthquake, a necessary criterion for judgement of sufficient mechanical earthquake and a simple expression of released energy by earthuake are presented. Based on the catastrophe theory analysis,a new assumption, simply called theory on induced earthquake by fault zone weakening and rockmass softening, is sugested reasonably explaining the relation between reservoir-induced earthquake and rock types,structures,water level,and the characteristic of b value of reservoir-induced earthguake sequence.We have a clear knowledge of reservoir-inuced earthquake mechanism from this paper discussion
1995, 3(1): 45-55.
In this paper,the characterics of the rupture of coal mine shaft wall in thick surface soils occured in East China recently are described. The engineering gelogical conditions of rupture of shaft wall are analysed. The parameters of deformation and strength of soil-concrete interaction on the interface of soil and shaft wall are studied. Moreover,regarding the interface of soil and shaft wall as interface elements,using elastic-plastic FEM,the interaction between soil and shaft wall due to the bottom aquifer losing water is modelled, the variation laws of the additional stresses of shaft wall with depth and water lowering of the bottom aquifer are obtained,and the inherent mechanism of the rupture of shaft wall is revealed.
In this paper,the characterics of the rupture of coal mine shaft wall in thick surface soils occured in East China recently are described. The engineering gelogical conditions of rupture of shaft wall are analysed. The parameters of deformation and strength of soil-concrete interaction on the interface of soil and shaft wall are studied. Moreover,regarding the interface of soil and shaft wall as interface elements,using elastic-plastic FEM,the interaction between soil and shaft wall due to the bottom aquifer losing water is modelled, the variation laws of the additional stresses of shaft wall with depth and water lowering of the bottom aquifer are obtained,and the inherent mechanism of the rupture of shaft wall is revealed.
1995, 3(1): 56-64.
In the Southern Tableland (Nanyuan)of Jingyang County,Shaanxi Province,the loess landslides often occur along the slope of the tableland,causing heavy casualties and serious economic losses.Landslides are not only produced by natural factors,such as tectonics,geomorphology, and climate,etc. but also by human activities. According to field investigations,the channeled surface water into fields is a dominant factor for loess landslides in this area.The groundwater table is rising with the expansion of irrigated area and the increase of irrigated water, so the pressure head of the s ope of the tableland greatly increases,the shearing strength of loess much decreases,wi h accelerating formation of landslides.Therefore, the rational irrigation and the control of rise of the groundwater table are a key measure to prevent loess landslide hazards and improve the geological environment on the slope of the Southern Tableland of Jingyang County,Shaanxi.
In the Southern Tableland (Nanyuan)of Jingyang County,Shaanxi Province,the loess landslides often occur along the slope of the tableland,causing heavy casualties and serious economic losses.Landslides are not only produced by natural factors,such as tectonics,geomorphology, and climate,etc. but also by human activities. According to field investigations,the channeled surface water into fields is a dominant factor for loess landslides in this area.The groundwater table is rising with the expansion of irrigated area and the increase of irrigated water, so the pressure head of the s ope of the tableland greatly increases,the shearing strength of loess much decreases,wi h accelerating formation of landslides.Therefore, the rational irrigation and the control of rise of the groundwater table are a key measure to prevent loess landslide hazards and improve the geological environment on the slope of the Southern Tableland of Jingyang County,Shaanxi.
1995, 3(1): 65-69.
The enfored effect of the prestressed cable bolts is determined by the value of prestress. The loads supplied by the cable bolts must be sufficient so that at all times the stability of rock mass is retained. The load losses of the cable bolts are produced by the deformation of rock mass depending on time,corrosion and different kinds of structures etc. These porduce the bad effect of enforcement.The paper mainly study the load losses produced by the deformation of rock mass depending on time. The load losses of the cable bolts can be found by.According to the visco-elastic properties of rock mass tf and at are established. Finally.the effect of the free and anchored length on decreasing the load losses is discussed.
The enfored effect of the prestressed cable bolts is determined by the value of prestress. The loads supplied by the cable bolts must be sufficient so that at all times the stability of rock mass is retained. The load losses of the cable bolts are produced by the deformation of rock mass depending on time,corrosion and different kinds of structures etc. These porduce the bad effect of enforcement.The paper mainly study the load losses produced by the deformation of rock mass depending on time. The load losses of the cable bolts can be found by.According to the visco-elastic properties of rock mass tf and at are established. Finally.the effect of the free and anchored length on decreasing the load losses is discussed.
1995, 3(1): 70-77.
Based on the recent progress in the inversion analysis methods viscoelasitc displace ment of the circular and noncircular tunnel surrounding rock,fiveviscoelastic mechanical model recognitions and parameter inversion theorems are put forward according to the inversive regularities of mechanical parameters analyitical solution of the tunnel sur rounding rock, and some computational examples and practical instances are given to make the necessary examination of the theorems obtained here.
Based on the recent progress in the inversion analysis methods viscoelasitc displace ment of the circular and noncircular tunnel surrounding rock,fiveviscoelastic mechanical model recognitions and parameter inversion theorems are put forward according to the inversive regularities of mechanical parameters analyitical solution of the tunnel sur rounding rock, and some computational examples and practical instances are given to make the necessary examination of the theorems obtained here.
1995, 3(1): 78-85.
The major engineering water project Wanjiazhai Diversion Project from Yellow Riv er to Shanxi Province,is famous for its lage scale.complex technology and high cost up to ten milliard yuans.Basing on a brief introduction to the general situation of this project.this paper ex pounds several geological problems emphatically which exist in the diversion tunnel and the measures which will be taken, and proves the feasibility of constructiog this project form the aspect of engineering geology.
The major engineering water project Wanjiazhai Diversion Project from Yellow Riv er to Shanxi Province,is famous for its lage scale.complex technology and high cost up to ten milliard yuans.Basing on a brief introduction to the general situation of this project.this paper ex pounds several geological problems emphatically which exist in the diversion tunnel and the measures which will be taken, and proves the feasibility of constructiog this project form the aspect of engineering geology.
1995, 3(1): 86-91.
Luoanjiang Irrigation-Reservoir Engineering Project was built during the first years after the foundation of P. R. C.,it is the one of the main water channels for irrigating more ten thousand mu land in the northern Guizhou,The 7.5 Flood Hazardoccurred in 1991 due to the extreme storm, river in spate,and underground stream back flow, resulting in high kinetie pressure. The bank slope and rockmass in which the unfavorable structural faces occur have undergone to on-beding landslide, blocked the mian channel and affected the inigation system seriously. The article analyses and evaluates the effects.of the landslide,its geological environment,structural features,the formation mechanism(landslide pattern and failure mechanism)and rockmass stability,as well as the genesis of landslide.
Luoanjiang Irrigation-Reservoir Engineering Project was built during the first years after the foundation of P. R. C.,it is the one of the main water channels for irrigating more ten thousand mu land in the northern Guizhou,The 7.5 Flood Hazardoccurred in 1991 due to the extreme storm, river in spate,and underground stream back flow, resulting in high kinetie pressure. The bank slope and rockmass in which the unfavorable structural faces occur have undergone to on-beding landslide, blocked the mian channel and affected the inigation system seriously. The article analyses and evaluates the effects.of the landslide,its geological environment,structural features,the formation mechanism(landslide pattern and failure mechanism)and rockmass stability,as well as the genesis of landslide.
1995, 3(1): 92-95.
This paper provides the chemical composition of groundwater in urban area of Nanjing and makes an evaluation of the erosion of groundwater in a construction site, and then analyzes the causes of erosion of groundwater.
This paper provides the chemical composition of groundwater in urban area of Nanjing and makes an evaluation of the erosion of groundwater in a construction site, and then analyzes the causes of erosion of groundwater.