1998 Vol. 6, No. 4
1998, 6(4): 289-300.
The middle and lower reaches of Jinshajiang River, flowing across the Hengduan south north tectonic belt, marked by intense neotectonism and frequent seismic activity, has relatively strong active tectonism accompanied with various endogenic geological hazards. In this case it seems necessary to conduct a quantitative assessment and zonation of the regional crustal stability for planning and construction of hydropower projects along the Jinshajiang river valley. Based on the quantitative system of classifying crustal stability, a number of elemental parameters, including tectonic background of the region, the crustal structure model, as well as seismological and geophysical parameters, are studied and the crustal stability is classified as stable, basically stable, sub stable, and unstable. Based on this system, Jinshajiang River basin is divided into 13 subzones. Finally, the stability for each subzone is determined as a grade by using comprehensive fuzzy mathematic method.
The middle and lower reaches of Jinshajiang River, flowing across the Hengduan south north tectonic belt, marked by intense neotectonism and frequent seismic activity, has relatively strong active tectonism accompanied with various endogenic geological hazards. In this case it seems necessary to conduct a quantitative assessment and zonation of the regional crustal stability for planning and construction of hydropower projects along the Jinshajiang river valley. Based on the quantitative system of classifying crustal stability, a number of elemental parameters, including tectonic background of the region, the crustal structure model, as well as seismological and geophysical parameters, are studied and the crustal stability is classified as stable, basically stable, sub stable, and unstable. Based on this system, Jinshajiang River basin is divided into 13 subzones. Finally, the stability for each subzone is determined as a grade by using comprehensive fuzzy mathematic method.
1998, 6(4): 301-304.
Presently the frequently held international geotechnology symposia reflect the desire of every countries in the world to solve its environmental problems. It implies that a new stage of environmental geotechnology has come. Combining with the situation of the discipline in China, analysis of the details of these symposia will help to improve our recognization of the present attractive topical subjects of environmental geotechnology and hence we play a role in solving environmental problems and sustainable development of economical society. This paper provides an integratation of the present attractive subjects and related techniques in international environmental geotechnology. Environmental problems are so extensive that this paper can not include all programs. Therefore, traditional contents of environmental geotechnology and geological hazards famaliar to researchers are ignored, but they are not unimportant.
Presently the frequently held international geotechnology symposia reflect the desire of every countries in the world to solve its environmental problems. It implies that a new stage of environmental geotechnology has come. Combining with the situation of the discipline in China, analysis of the details of these symposia will help to improve our recognization of the present attractive topical subjects of environmental geotechnology and hence we play a role in solving environmental problems and sustainable development of economical society. This paper provides an integratation of the present attractive subjects and related techniques in international environmental geotechnology. Environmental problems are so extensive that this paper can not include all programs. Therefore, traditional contents of environmental geotechnology and geological hazards famaliar to researchers are ignored, but they are not unimportant.
1998, 6(4): 305-311.
In this paper, characteristics of the slope engineering on the open pit are expounded, the research of the stability of the slope on the open pit and the theory achievement of the stability of slope are reviewed, the peculiarity on the research of the stability of the open pit slope are demonstrated, the technique route and methods are demonstrated.
In this paper, characteristics of the slope engineering on the open pit are expounded, the research of the stability of the slope on the open pit and the theory achievement of the stability of slope are reviewed, the peculiarity on the research of the stability of the open pit slope are demonstrated, the technique route and methods are demonstrated.
1998, 6(4): 312-318.
In the course of ore mining, there is often a situation of combined underground and open pit minings. According to the relation between spatial positions of stopes, parts the influenced realms by different mining excavations are overlapping. It results in the interaction and superimposition of two kinds of mining effect and hence forms a composite dynamic system. Thus, the deformation mechanism of slope rockmass becomes more complicated and differs from that caused only by open pit mining. However, in treatment of the conventional method for slope stability, this kind of influence is usually used. Its result was different from the real situation. Therefore, in this paper an evaluating method is derived on the basis of theoretical analysis and case study. It provides scientific basis for design and safe production of these mines with continuous excavation.
In the course of ore mining, there is often a situation of combined underground and open pit minings. According to the relation between spatial positions of stopes, parts the influenced realms by different mining excavations are overlapping. It results in the interaction and superimposition of two kinds of mining effect and hence forms a composite dynamic system. Thus, the deformation mechanism of slope rockmass becomes more complicated and differs from that caused only by open pit mining. However, in treatment of the conventional method for slope stability, this kind of influence is usually used. Its result was different from the real situation. Therefore, in this paper an evaluating method is derived on the basis of theoretical analysis and case study. It provides scientific basis for design and safe production of these mines with continuous excavation.
1998, 6(4): 319-325.
As a criterion for prediction of landslide it is insufficient that a steep rise shows in a displacement-time curve for a observation point on or in a slope. And some other criterions are not sufficient as well. The views are experientially and theoretically set forth in the paper.
As a criterion for prediction of landslide it is insufficient that a steep rise shows in a displacement-time curve for a observation point on or in a slope. And some other criterions are not sufficient as well. The views are experientially and theoretically set forth in the paper.
1998, 6(4): 326-332.
The memory function of rock includes the influence of residual stress on mechanical behavior of material, the freeze of stress, and the memory of consolidated stress. This paper describes theoretical bases, mechanical models, and calculation methods for the above three types of stresses. Some engineering calculation examples indicate their significance in analysis of deformation and stability of rock masses.
The memory function of rock includes the influence of residual stress on mechanical behavior of material, the freeze of stress, and the memory of consolidated stress. This paper describes theoretical bases, mechanical models, and calculation methods for the above three types of stresses. Some engineering calculation examples indicate their significance in analysis of deformation and stability of rock masses.
1998, 6(4): 333-339.
In this Paper, from the concept of link ratio of joints in engeneering geology, a mechanical modal for discontinuous rock mass with one set of joints is given and some calculation formula are developed, and then the whole process of a slip sureface gradually evolving from the potential slip sureface of a slope under the effect of hydro static pressure is simulated and analyzed. Finally a valuable conclusion is drawn.
In this Paper, from the concept of link ratio of joints in engeneering geology, a mechanical modal for discontinuous rock mass with one set of joints is given and some calculation formula are developed, and then the whole process of a slip sureface gradually evolving from the potential slip sureface of a slope under the effect of hydro static pressure is simulated and analyzed. Finally a valuable conclusion is drawn.
1998, 6(4): 340-343.
A viscous elastic rheological model of 3 parts is used to simulate the rheology of roadbed soil. From the observation data obtained during construction, the geological mechanical parameters are obtained by inversive analyiss, adopting viscous elastic FEM and non linear optimal method and the roadbed settlement after construction is calculated. Then a back analysis program of viscous elastic FEM for soil is given. The back analysis was performed for Shanghai Nanjing speedway based on the program and the satisfactory results were obtained.
A viscous elastic rheological model of 3 parts is used to simulate the rheology of roadbed soil. From the observation data obtained during construction, the geological mechanical parameters are obtained by inversive analyiss, adopting viscous elastic FEM and non linear optimal method and the roadbed settlement after construction is calculated. Then a back analysis program of viscous elastic FEM for soil is given. The back analysis was performed for Shanghai Nanjing speedway based on the program and the satisfactory results were obtained.
1998, 6(4): 344-350.
A grey system model, the dynamic model GM(1,1) g model, for recognition of seismogeochemical precursor is studied. Dissolved hydrogen gas dynamic change in Langanshi hot well, Beijing is used in the study here. The seismic precursor was found 15 days before the Fengzhen earthquake, Nei Monggol on August 13, 1981, M s=5.8 ). The concept of recognition index M(t)for the dynamic precursor is firstly suggested in this paper. The index is more effective than the static index in recongniyion of seismic precursor.
A grey system model, the dynamic model GM(1,1) g model, for recognition of seismogeochemical precursor is studied. Dissolved hydrogen gas dynamic change in Langanshi hot well, Beijing is used in the study here. The seismic precursor was found 15 days before the Fengzhen earthquake, Nei Monggol on August 13, 1981, M s=5.8 ). The concept of recognition index M(t)for the dynamic precursor is firstly suggested in this paper. The index is more effective than the static index in recongniyion of seismic precursor.
1998, 6(4): 351-354.
In the paper a newly developed numerical code, RFPA 2D (Rock Failure Process Analysis), is applied to study of rock failure process caused by excavation. bases on nonlinear deformation of rock caused by heterogeneity and anisotropy.
In the paper a newly developed numerical code, RFPA 2D (Rock Failure Process Analysis), is applied to study of rock failure process caused by excavation. bases on nonlinear deformation of rock caused by heterogeneity and anisotropy.
1998, 6(4): 355-361.
This paper studied fractal characteristics of essential elements of rock mass structure, such as shape of discontinuity, thickness of discontinuity, distribution of discontinuities, distribution of structural body, dispersion of orientation of discontinuities, pore distribution, and surface shape of particles, so as to improv equantitative description and a new method for quantitative evaluation of rock engineering geological conditions.
This paper studied fractal characteristics of essential elements of rock mass structure, such as shape of discontinuity, thickness of discontinuity, distribution of discontinuities, distribution of structural body, dispersion of orientation of discontinuities, pore distribution, and surface shape of particles, so as to improv equantitative description and a new method for quantitative evaluation of rock engineering geological conditions.
1998, 6(4): 362-367.
In the stimulation experiment of slope displacement field caused by open pit excavation, theres great difference in the results of stimulation between whether or not the effect of self weight body force on mechanical properties of the modal material during solidification is considered. The above conclusion is proved by two experiments in contrast with each other in the paper.
In the stimulation experiment of slope displacement field caused by open pit excavation, theres great difference in the results of stimulation between whether or not the effect of self weight body force on mechanical properties of the modal material during solidification is considered. The above conclusion is proved by two experiments in contrast with each other in the paper.
1998, 6(4): 368-374.
On the base of geological prospecting, a three dimensional physical model is used in experimental study of the stability of high steep slope in consideration of different slope angles and the power excavation of the slope. It further proves the rationality of previous design angles for the mine slope.
On the base of geological prospecting, a three dimensional physical model is used in experimental study of the stability of high steep slope in consideration of different slope angles and the power excavation of the slope. It further proves the rationality of previous design angles for the mine slope.
1998, 6(4): 375-380.
In order to obtain the variation and distribution properties of stress and strain at the key parts of a model, especially at the safe area from an external burden, we first apply the acoustic testing to the comparatively large model experiment using the small-size sensors developed by ourselves. We obtained the testing results during the whole experiment process. The results and those from other testing methods are complement and verification to each other. The identical expecting results are obtained.
In order to obtain the variation and distribution properties of stress and strain at the key parts of a model, especially at the safe area from an external burden, we first apply the acoustic testing to the comparatively large model experiment using the small-size sensors developed by ourselves. We obtained the testing results during the whole experiment process. The results and those from other testing methods are complement and verification to each other. The identical expecting results are obtained.