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Editor Work1999 Vol. 7, No. 1
Previous Issue
1999, 7(1): 3-8.
Abstract
252KB
This article emphasizes a prediction of overbreak,the unstable wedge, for openings in jointed rock mass. Firstly, the basic concept of overbreak in opening, its main cause, and the estimating method are described. Secondly, the calculation softwares and their characteristics for opening overbreak are analyzed and compared. Then, a calculation software edited by the authors is introduced. Finely,a calculation case is given, from field investigation to statistical analysis of the parameters, a general formula for an unstable wedge is inferred; after that, the main factors affecting the unstable wedge are shown. The prediction result provides a basis for treating the overbreak.
This article emphasizes a prediction of overbreak,the unstable wedge, for openings in jointed rock mass. Firstly, the basic concept of overbreak in opening, its main cause, and the estimating method are described. Secondly, the calculation softwares and their characteristics for opening overbreak are analyzed and compared. Then, a calculation software edited by the authors is introduced. Finely,a calculation case is given, from field investigation to statistical analysis of the parameters, a general formula for an unstable wedge is inferred; after that, the main factors affecting the unstable wedge are shown. The prediction result provides a basis for treating the overbreak.
1999, 7(1): 9-14.
A lot of facts indicate that the deformation and failure processes of rockmass during surface and underground excavations are of different non linear behaviors.In this paper,an effect of media non linear haviours on deformation and stress of rockmass during excavation is discussed firstly and the numerical simulation method for excavation is modified.Further,a series of non linear self organization models for rockmass fracture and movement are established.They provide a systematic description of the whole process, from micro fracture ofrock elements, formation and evolution of slip surface, to entire failure. Based on the above discussed,a non linear dynamic equation for describing rockmassmovement during excavation is formulated.
A lot of facts indicate that the deformation and failure processes of rockmass during surface and underground excavations are of different non linear behaviors.In this paper,an effect of media non linear haviours on deformation and stress of rockmass during excavation is discussed firstly and the numerical simulation method for excavation is modified.Further,a series of non linear self organization models for rockmass fracture and movement are established.They provide a systematic description of the whole process, from micro fracture ofrock elements, formation and evolution of slip surface, to entire failure. Based on the above discussed,a non linear dynamic equation for describing rockmassmovement during excavation is formulated.
1999, 7(1): 15-19.
In this paper a preliminary research on potential effects of underground engineering on groundwater environment are discussed. The effect is mainly as follows: blocking the flowout of ancient channel water, causing the fluctuation of ground water level, and inducing the interconnection between groundwater and lakewater. All the effect will result in the aggravation of ground water contamination and the deterioration of ecological environment.
In this paper a preliminary research on potential effects of underground engineering on groundwater environment are discussed. The effect is mainly as follows: blocking the flowout of ancient channel water, causing the fluctuation of ground water level, and inducing the interconnection between groundwater and lakewater. All the effect will result in the aggravation of ground water contamination and the deterioration of ecological environment.
1999, 7(1): 20-24.
Author of this paper attempts to carry out surrounding rock classification through rock stress and rock behaviour measuremens by sleeve fracturing technique. In this paper surrounding rock stability criterian and rock classification principle are proposed and application of the rock stability analysis method to rock stress and shaft lining stress measurement in colliery is described.
Author of this paper attempts to carry out surrounding rock classification through rock stress and rock behaviour measuremens by sleeve fracturing technique. In this paper surrounding rock stability criterian and rock classification principle are proposed and application of the rock stability analysis method to rock stress and shaft lining stress measurement in colliery is described.
1999, 7(1): 25-29.
The whole process of geological hazard can be distinguished into three stages: the hazard preparating stage, activating stage, and recoving stage after its occurrence. The hazard evaluation includs systematic investigation, statics, analysis and estimation. The focus of evaluation is to estimate the activity of hazard. On the basis of the described theory of geological hazard condition evalution, this paper provides an evalution of land slide hazard in Wanxian City.
The whole process of geological hazard can be distinguished into three stages: the hazard preparating stage, activating stage, and recoving stage after its occurrence. The hazard evaluation includs systematic investigation, statics, analysis and estimation. The focus of evaluation is to estimate the activity of hazard. On the basis of the described theory of geological hazard condition evalution, this paper provides an evalution of land slide hazard in Wanxian City.
1999, 7(1): 30-34.
In this paper, Xian ground fracture and surface subsidence hazard are analyzed and predicted by using projection tracing technique. The result has an indicative significance for centrolling control these hazards.
In this paper, Xian ground fracture and surface subsidence hazard are analyzed and predicted by using projection tracing technique. The result has an indicative significance for centrolling control these hazards.
1999, 7(1): 35-39.
Paleogravel bed around Nanjing city is one of primary Cenozoic strata in Nanjing area. The study lays special stress on its geological charactevistics, material composition, pedogenesis diagenesis, and mechanical properties.
Paleogravel bed around Nanjing city is one of primary Cenozoic strata in Nanjing area. The study lays special stress on its geological charactevistics, material composition, pedogenesis diagenesis, and mechanical properties.
1999, 7(1): 40-45.
Generally speaking,a complex slope is composed of different kinds of rocks and the stability is controlled by the rock structure and graduall formation of slope slip surface. Based on these characteristics, in this paper a block theory method is suggested for determination of slope slip surface and analysis of the stability of a large slope engineering by Sarma equilibrium method and other slip surface shape, the results verfied the block theory method.
Generally speaking,a complex slope is composed of different kinds of rocks and the stability is controlled by the rock structure and graduall formation of slope slip surface. Based on these characteristics, in this paper a block theory method is suggested for determination of slope slip surface and analysis of the stability of a large slope engineering by Sarma equilibrium method and other slip surface shape, the results verfied the block theory method.
1999, 7(1): 46-53.
In the paper, the theories of System Engineering and Fuzzy Mathematics are applied to construct a multiperson and multilayer fuzzy comprehensive evaluation model for rock slope stability according to the characters that the evaluation indexes are multilayer and that the evaluation process is completed by many people in engineering geology evaluation of slope stability.The main factors affecting the stability of rock slope are analyzed, a structure of multilayer ordered evaluation tree (MOET) is set up for the comprehensive evaluation of rock slope stability, and the quantification methods are suggested for evaluation indexes of MOET which include four kinds of subordinate functions and an integrated index-weight determination system. then a fuzzy reasoning algorithm is formulated on the basis of slope engineering knowledge, a computer program flow chart of the whole comprehensive evaluation process and a computer program system for multiperson and multilayer fuzzy comprehensive evaluation of rock slope stability(SM2FCERS2) ard developed. Finally, an example is used to show the effectiveness of the system.
In the paper, the theories of System Engineering and Fuzzy Mathematics are applied to construct a multiperson and multilayer fuzzy comprehensive evaluation model for rock slope stability according to the characters that the evaluation indexes are multilayer and that the evaluation process is completed by many people in engineering geology evaluation of slope stability.The main factors affecting the stability of rock slope are analyzed, a structure of multilayer ordered evaluation tree (MOET) is set up for the comprehensive evaluation of rock slope stability, and the quantification methods are suggested for evaluation indexes of MOET which include four kinds of subordinate functions and an integrated index-weight determination system. then a fuzzy reasoning algorithm is formulated on the basis of slope engineering knowledge, a computer program flow chart of the whole comprehensive evaluation process and a computer program system for multiperson and multilayer fuzzy comprehensive evaluation of rock slope stability(SM2FCERS2) ard developed. Finally, an example is used to show the effectiveness of the system.
1999, 7(1): 54-59.
By means of 3D isoparametric FEM, a numerical simulation has been done on three schemes of initial seepage field, seepage field after impounding of Wanjiazhai Reservoir and seepage field after impounding of Longkou Reservoir at the vadose region around future Longkou Dam. And the corresponding seepage flow was calculated. These results are significant for decision of the practical project.
By means of 3D isoparametric FEM, a numerical simulation has been done on three schemes of initial seepage field, seepage field after impounding of Wanjiazhai Reservoir and seepage field after impounding of Longkou Reservoir at the vadose region around future Longkou Dam. And the corresponding seepage flow was calculated. These results are significant for decision of the practical project.
CALCULATION OF PLASTIC DEFORMATION STABILITY OF LIUFANGDI MULTI LAYER SOIL DAM FOUNDATION IN HUAINAN
1999, 7(1): 60-64.
In this paper the authors analyse and study Fourier series formula of development of the dam body load on the stepped Liufangdi and calculation method for the dam foundation with some soil layers,and make an evaluation of the plastic deformation stability of the dam foundation on the basis of computed stress and identified plastic deformation in the dam foundation.
In this paper the authors analyse and study Fourier series formula of development of the dam body load on the stepped Liufangdi and calculation method for the dam foundation with some soil layers,and make an evaluation of the plastic deformation stability of the dam foundation on the basis of computed stress and identified plastic deformation in the dam foundation.
1999, 7(1): 65-71.
The physical mechanical parameters of intercalated gouge in layered weak zones are the basic parameters for evaluation of rockmass stability. A large number of studies show that there is a better relationship between the physical mechanical properties of intercalated gouge and its natural confining pressure.Therefore,the simulation study of intercalated gouge was done in labortory, by using the compression law of soil and the principle of gravity compaction of sediments, and the simulation effectiveness is evaluated. The result provides a new way for evaluating and predicting the physical mechanical parameters of intercalated gouge in layered weak zones.
The physical mechanical parameters of intercalated gouge in layered weak zones are the basic parameters for evaluation of rockmass stability. A large number of studies show that there is a better relationship between the physical mechanical properties of intercalated gouge and its natural confining pressure.Therefore,the simulation study of intercalated gouge was done in labortory, by using the compression law of soil and the principle of gravity compaction of sediments, and the simulation effectiveness is evaluated. The result provides a new way for evaluating and predicting the physical mechanical parameters of intercalated gouge in layered weak zones.
1999, 7(1): 72-76.
A new technique and method for non destructive test of anchoring quality of rock bolts is introduced. By the simulation test in laboratory, the features of reflective phase and energetic attenuation of sonic frequency stress wave in the anchoring system are analysed, and the determination of anchoring force in non destructive drawing test is described. The results are successfully applied to the construction quality test of anchoring engineering in the First Coal Mine of Panji.
A new technique and method for non destructive test of anchoring quality of rock bolts is introduced. By the simulation test in laboratory, the features of reflective phase and energetic attenuation of sonic frequency stress wave in the anchoring system are analysed, and the determination of anchoring force in non destructive drawing test is described. The results are successfully applied to the construction quality test of anchoring engineering in the First Coal Mine of Panji.
1999, 7(1): 77-81.
This paper briefly discusses present bolt support design theories and its application status. Main reasons are pointed out and excavation types must be considered when the support design theories are used to determine bolt parameters. Then openings are classified into three groups and the characteristics and rules of support design for each group are indicated. Considering features of the openings which belong to third group, the engineering analogue and empirical method are used in mines. So a neural net design system for bolt support design is developed and applied to district No.2 of Jinchuan nickel mine.
This paper briefly discusses present bolt support design theories and its application status. Main reasons are pointed out and excavation types must be considered when the support design theories are used to determine bolt parameters. Then openings are classified into three groups and the characteristics and rules of support design for each group are indicated. Considering features of the openings which belong to third group, the engineering analogue and empirical method are used in mines. So a neural net design system for bolt support design is developed and applied to district No.2 of Jinchuan nickel mine.
1999, 7(1): 82-88.
The numerical simulation results show that equivalence in continuum model of fluid flow in fractured rock in terms of flux and seepage forces deformation can not be deduced from each other; that continuum model is not applicable to fractures with the remarkable difference in hydromechanical features; but variation of its hydraulic parameters with stress can be easily obtained through the numerical simulation. Results from the field data indicate that it would be too rough to assume that fractures in rock are completely interconnected, and that in situ experiment result seems to reveal the behavior of fractured rock not on the RE V scale, but on the local scale.
The numerical simulation results show that equivalence in continuum model of fluid flow in fractured rock in terms of flux and seepage forces deformation can not be deduced from each other; that continuum model is not applicable to fractures with the remarkable difference in hydromechanical features; but variation of its hydraulic parameters with stress can be easily obtained through the numerical simulation. Results from the field data indicate that it would be too rough to assume that fractures in rock are completely interconnected, and that in situ experiment result seems to reveal the behavior of fractured rock not on the RE V scale, but on the local scale.
1999, 7(1): 89-94.
D numerical simulation of underground excavation in high rock slope with software Rocky was carried out for study of Maya rock slope engineering related to Shuibuya hydroelect power project. The numerical simulation of mechanical situation and rock pillar stability of tunnel engineering in the slope and slope cuting measures for the stability control are illustrated in detail. These studies also consist of earthquake dynamic simulation of slope engineering in practice. The numerical simulation result shows that the study is reasonable and practical.
D numerical simulation of underground excavation in high rock slope with software Rocky was carried out for study of Maya rock slope engineering related to Shuibuya hydroelect power project. The numerical simulation of mechanical situation and rock pillar stability of tunnel engineering in the slope and slope cuting measures for the stability control are illustrated in detail. These studies also consist of earthquake dynamic simulation of slope engineering in practice. The numerical simulation result shows that the study is reasonable and practical.
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