1993 Vol. 1, No. 1
The action and effect of groundwater on engineering projects and their environments are increasingly apparent and more deeply known in the practice.The problem is not a pure hydrogeological subject. It is essentially a problem concerning with hydrogeology and engineering geology and is called temporally engineering-hydrogeolgical problem, which is found in the process of engineering construction and in study of environmental geology and expresses various engineering geological and hydrogeological problems due to the action of groundwater. In order to complete deciphering the problem, it is illustrated by the examples of interactions between water and rock, bedrock pit discharge and sand flow by crypto-erosion, foundation subsidence and loess subsidence, frozen damage of road surface and tunnel water burst, mining pitout burst and shaft failure, dam basement leakage and stability, slide-stable dam basement, and geological hazards due to groundwater. The purpose of the paper is to indicate a direction which is worthy to be studied and must be highly emphasized.
The action and effect of groundwater on engineering projects and their environments are increasingly apparent and more deeply known in the practice.The problem is not a pure hydrogeological subject. It is essentially a problem concerning with hydrogeology and engineering geology and is called temporally engineering-hydrogeolgical problem, which is found in the process of engineering construction and in study of environmental geology and expresses various engineering geological and hydrogeological problems due to the action of groundwater. In order to complete deciphering the problem, it is illustrated by the examples of interactions between water and rock, bedrock pit discharge and sand flow by crypto-erosion, foundation subsidence and loess subsidence, frozen damage of road surface and tunnel water burst, mining pitout burst and shaft failure, dam basement leakage and stability, slide-stable dam basement, and geological hazards due to groundwater. The purpose of the paper is to indicate a direction which is worthy to be studied and must be highly emphasized.
1993, 1(1): 7-13.
Study of the regional crustal stability of engineering sites is one of the subjects of engineering geology in China. The research history is outlined, developmental stages are divided,different opinions are introduced, new situations faced at present and future development tendencies are analysed in this paper. It indicates that selecting and evaluating relative stable landmass (called safety island) will be a basic goal for important engineering sites in the active tectonic areas.
Study of the regional crustal stability of engineering sites is one of the subjects of engineering geology in China. The research history is outlined, developmental stages are divided,different opinions are introduced, new situations faced at present and future development tendencies are analysed in this paper. It indicates that selecting and evaluating relative stable landmass (called safety island) will be a basic goal for important engineering sites in the active tectonic areas.
1993, 1(1): 14-18.
The author suggested the Theory on Structure-Controlled Rockmass as a fundamental theory of rockmass mechanics in 1984 after a lot of practical and rescarch works in a long time and comprehensively, schematically investigated the basic law of defomation, failure and mechanical properties of rockmass, guided by the Theory on Stucture-Controlled Rockmass. The author suggested a series of viewpoints, that is, the rockmass deformation was contributed by the deformation of rockmass material and the deformation of rockmass structure. The rockmass failure was controlled by the rockmass material and rockmass structure. The mechanical properties of rockmass have been determined not only by the mechanical properties of rockmass material, but also by the mechanical effect of rockmass structure and mechanical effect of environmental factors (earth stress, underground water, earth temperature). On this basis, the author suggested that, the rockmass may be classified into four types of mechanical medium, that is continuous medium, jointed medium, blocky medium and slabbed medium, and that, the rockmass mechanics is a mechanical system, consisting of continuous medium, jointed medium, blocky medium and slabbed medium. Thereby, an integreted theory system of Rockmass Structure Mechanics was systematized by the author.
The author suggested the Theory on Structure-Controlled Rockmass as a fundamental theory of rockmass mechanics in 1984 after a lot of practical and rescarch works in a long time and comprehensively, schematically investigated the basic law of defomation, failure and mechanical properties of rockmass, guided by the Theory on Stucture-Controlled Rockmass. The author suggested a series of viewpoints, that is, the rockmass deformation was contributed by the deformation of rockmass material and the deformation of rockmass structure. The rockmass failure was controlled by the rockmass material and rockmass structure. The mechanical properties of rockmass have been determined not only by the mechanical properties of rockmass material, but also by the mechanical effect of rockmass structure and mechanical effect of environmental factors (earth stress, underground water, earth temperature). On this basis, the author suggested that, the rockmass may be classified into four types of mechanical medium, that is continuous medium, jointed medium, blocky medium and slabbed medium, and that, the rockmass mechanics is a mechanical system, consisting of continuous medium, jointed medium, blocky medium and slabbed medium. Thereby, an integreted theory system of Rockmass Structure Mechanics was systematized by the author.
1993, 1(1): 19-25.
The Three-Gorge Engineering Project which attracts worldwide attension now enters a clucial construction stage. In this paper the long-term engineering geological exploration and reasearch of the Three-Gorge project area are described from the regional stability and seismic risk, engineering geology of the reservoir area and environmental geology, reservoir-induced earthquake, engineering geology of dam site and biuldings, and natural construction materials, and an emphasis is made on the geological and seismological problems of the Three-Gorge engineering project. Finally, an experiential summarizing is made on the geological exploration of the huge engineering project.
The Three-Gorge Engineering Project which attracts worldwide attension now enters a clucial construction stage. In this paper the long-term engineering geological exploration and reasearch of the Three-Gorge project area are described from the regional stability and seismic risk, engineering geology of the reservoir area and environmental geology, reservoir-induced earthquake, engineering geology of dam site and biuldings, and natural construction materials, and an emphasis is made on the geological and seismological problems of the Three-Gorge engineering project. Finally, an experiential summarizing is made on the geological exploration of the huge engineering project.
1993, 1(1): 26-35.
The problems of urban environmental geotechnology are the hot spot of engineering geology and geotechnique at present. It is considered and discussed that the foundation instability in large cities, environmental water conservancy, and environmental pollution are the three main problems of the environmental geotechnology in urban areas. Basing on the principles of systematic science, this paper gives five basic notions on the research methodology of environmental geotechnique which are concerned by many research workers.
The problems of urban environmental geotechnology are the hot spot of engineering geology and geotechnique at present. It is considered and discussed that the foundation instability in large cities, environmental water conservancy, and environmental pollution are the three main problems of the environmental geotechnology in urban areas. Basing on the principles of systematic science, this paper gives five basic notions on the research methodology of environmental geotechnique which are concerned by many research workers.
1993, 1(1): 36-46.
The Karst water inflow system is analysed by using systematical and cybernetic methods in this paper. Using the data of geologic configuration, hydrochemical field and isotopic field to synthesize the relevant information, we set forth the feeding source and range of karst pouring water and the relationship between supplying and draining in detail. The hydrogeological conceptual model and mathematical model for karst water inflow are estabilished more realistically, and its pouring process is simulated numerically. Finally, we study the mechanism of surface collapse caused by water pouring and put forth its treatment project for ensuring the safety of railway transportation.
The Karst water inflow system is analysed by using systematical and cybernetic methods in this paper. Using the data of geologic configuration, hydrochemical field and isotopic field to synthesize the relevant information, we set forth the feeding source and range of karst pouring water and the relationship between supplying and draining in detail. The hydrogeological conceptual model and mathematical model for karst water inflow are estabilished more realistically, and its pouring process is simulated numerically. Finally, we study the mechanism of surface collapse caused by water pouring and put forth its treatment project for ensuring the safety of railway transportation.
1993, 1(1): 47-50.
This paper on the basis of summarizing underground space excavation and utilization in urban areas of China, describes the problems on soil stability and deformation, groundwater investigation and management, relation of excavation supporting to geological conditions, as well as construction impact upon existing structures, and then sets forth the future research directions.
This paper on the basis of summarizing underground space excavation and utilization in urban areas of China, describes the problems on soil stability and deformation, groundwater investigation and management, relation of excavation supporting to geological conditions, as well as construction impact upon existing structures, and then sets forth the future research directions.
1993, 1(1): 51-64.
The slope movement above the mined-out area is different from the deformation and failure of general slope and overlying strata in mine area. It is an effect of both the site movements and mechanisms. This study leads to establish a new research field of mountain Environmental Engineering Geology. Hengshan slope adjacent to a power plant forms a low-angle and downdip structure mountain, and there are several coal seams beneath it. Based on analysis of the structural characteristics of low-angle rock layer, this paper deals with the mechanical properties of weak interlayers on the slope. It is considered that the weak interlayers play a leading role in the lateral movement of the slope. According to detailed field investigation and analysis of displacement data obtained, it is founded that the deformation of rock mass of the slope is mainly controlled by underground mined-out area, and collapse as well as the creeping of the rock mass on the pre-slope toward the landsurface occur. Furthermore, slope deformation process and characteristics associated with underground mine collapse were studied using geomechanical modelling and elastic-plastic finite element method. The regularity of stress change within the slope caused by mine collapsing beneath the slope is analysed. It is showed that the deformation, displacement and failure of rock formations are through the overlying strata to the landsurface of the slope, and that the weak interlayer creeping induced by mine collapsing beneath the slope leads to the slope lateral movement. The surface doming of power plant area is caused by pre-slope rock mass pushing against the basement soil. By comparing the modelling results to real deformation and displacement data and geological indications, the collapse arching effect, the effect of additional push creeping and the damaging effect of collapse arching which were induced by underground coal mining, are analysed in detail and proposed. Thereby, this paper proposed also the composite mechanism of composite movement within the composite stress field and composite boundary surfaces, associated with the collapsing of the overlying strata about the slope downdip structure mountain. The typical geological model for the lateral movement of low-angle rock formation on the slope has been put forward.
The slope movement above the mined-out area is different from the deformation and failure of general slope and overlying strata in mine area. It is an effect of both the site movements and mechanisms. This study leads to establish a new research field of mountain Environmental Engineering Geology. Hengshan slope adjacent to a power plant forms a low-angle and downdip structure mountain, and there are several coal seams beneath it. Based on analysis of the structural characteristics of low-angle rock layer, this paper deals with the mechanical properties of weak interlayers on the slope. It is considered that the weak interlayers play a leading role in the lateral movement of the slope. According to detailed field investigation and analysis of displacement data obtained, it is founded that the deformation of rock mass of the slope is mainly controlled by underground mined-out area, and collapse as well as the creeping of the rock mass on the pre-slope toward the landsurface occur. Furthermore, slope deformation process and characteristics associated with underground mine collapse were studied using geomechanical modelling and elastic-plastic finite element method. The regularity of stress change within the slope caused by mine collapsing beneath the slope is analysed. It is showed that the deformation, displacement and failure of rock formations are through the overlying strata to the landsurface of the slope, and that the weak interlayer creeping induced by mine collapsing beneath the slope leads to the slope lateral movement. The surface doming of power plant area is caused by pre-slope rock mass pushing against the basement soil. By comparing the modelling results to real deformation and displacement data and geological indications, the collapse arching effect, the effect of additional push creeping and the damaging effect of collapse arching which were induced by underground coal mining, are analysed in detail and proposed. Thereby, this paper proposed also the composite mechanism of composite movement within the composite stress field and composite boundary surfaces, associated with the collapsing of the overlying strata about the slope downdip structure mountain. The typical geological model for the lateral movement of low-angle rock formation on the slope has been put forward.
1993, 1(1): 65-73.
The general method of applying catastrophe theory to engineering geology is proposed briefly in this paper. The current situation of application ofCUSP catastrophe theory to engineering geology is introduced by practicalexamples, which include stability analysis of layer structure slopes.roof collapse of cavities and active faults, and forecast of landslide time etc. Meanwhile, It looks forward to the perspective of application.
The general method of applying catastrophe theory to engineering geology is proposed briefly in this paper. The current situation of application ofCUSP catastrophe theory to engineering geology is introduced by practicalexamples, which include stability analysis of layer structure slopes.roof collapse of cavities and active faults, and forecast of landslide time etc. Meanwhile, It looks forward to the perspective of application.
1993, 1(1): 74-84.
In this paper a u-t curve for the whole process of deformation of the fractured weak rocks during all-section excavating is described from the data of in-situ successive monitoring and measurement for more than ten years, the deformation rate, amount and their effects in time and space are suggested, and the effects of main factors, such as the engineering geological properties, burial depth, opening diameters, excavation modes and in-time supporting, on the deformation characteristics of rocks are discussed. Then the criteria for division and discrimination of stability behaviors of rocks, principles for prediction of instability risk, critera for controlling deformation, principles for determining early support resistance and for selecting optimum period of late supporting, and rational excavation mode are proposed for specific engineering project.
In this paper a u-t curve for the whole process of deformation of the fractured weak rocks during all-section excavating is described from the data of in-situ successive monitoring and measurement for more than ten years, the deformation rate, amount and their effects in time and space are suggested, and the effects of main factors, such as the engineering geological properties, burial depth, opening diameters, excavation modes and in-time supporting, on the deformation characteristics of rocks are discussed. Then the criteria for division and discrimination of stability behaviors of rocks, principles for prediction of instability risk, critera for controlling deformation, principles for determining early support resistance and for selecting optimum period of late supporting, and rational excavation mode are proposed for specific engineering project.
1993, 1(1): 85-92.
On the basis of summarizing the definitions of initial pressure for subsidence of moist ground given by others, the paper gives a definition that the initial pressure for subsidence is a pressure to which the coefficient of subsidence controlled to be 0.015 corresponds after the loess was water-soaked. The pressure is a technical parameter of many performances for design of soil foundations, ground treatments, and elevations of subsidence of moist ground. The initial subsidence pressure has its regional variation regularity. From Qinghai in the west to Zhongzhou in the east, it appears to be higher at both ends and lower in the middle, and higher in the east and lower in the west in general. The initial subsidence pressure increases with depth in longitudinal direction in all loess areas. To understand and grasp these two regularities will help us to fully use loess foundations and choose the best technical option for their reform. Evaluation of the types pf soil foundation subsidence due to initial subsidence pressure can give the Highest, confidence meanwhile, the initial subsidence pressure is also a parameter for determining ground strength and forecasting soil deformation. The pressure value is used as a foundation bearing capacity in engineering at which the foundation can not produce subsidence deformation, which can not exceed the permissible deformation. Because the initial subsidence pressure is a load at elastic deformation stage after loess soakage. The load-relevant deformation is almost at 0.8 cm. To test the initital subsidence pressure, the single-and couple-line methods can be used in laboratory. But the couple-line method is usually adopted in production. To test the pressure in the field, a water saturation method is used, and pressure plate area of 2500 cm2 is adopted.
On the basis of summarizing the definitions of initial pressure for subsidence of moist ground given by others, the paper gives a definition that the initial pressure for subsidence is a pressure to which the coefficient of subsidence controlled to be 0.015 corresponds after the loess was water-soaked. The pressure is a technical parameter of many performances for design of soil foundations, ground treatments, and elevations of subsidence of moist ground. The initial subsidence pressure has its regional variation regularity. From Qinghai in the west to Zhongzhou in the east, it appears to be higher at both ends and lower in the middle, and higher in the east and lower in the west in general. The initial subsidence pressure increases with depth in longitudinal direction in all loess areas. To understand and grasp these two regularities will help us to fully use loess foundations and choose the best technical option for their reform. Evaluation of the types pf soil foundation subsidence due to initial subsidence pressure can give the Highest, confidence meanwhile, the initial subsidence pressure is also a parameter for determining ground strength and forecasting soil deformation. The pressure value is used as a foundation bearing capacity in engineering at which the foundation can not produce subsidence deformation, which can not exceed the permissible deformation. Because the initial subsidence pressure is a load at elastic deformation stage after loess soakage. The load-relevant deformation is almost at 0.8 cm. To test the initital subsidence pressure, the single-and couple-line methods can be used in laboratory. But the couple-line method is usually adopted in production. To test the pressure in the field, a water saturation method is used, and pressure plate area of 2500 cm2 is adopted.