Spatial Prediction Theory For Disease Of High Engineering Slope And Its Application

In this thesis, the fundamental theory of the slope damage involving the types of damage of slopes, its affecting factors, and slope geological structure has been studied first. Based on the research qualitative prediction methods for the slope disease are discussed. In order to derive a new constitutive equation it start with results of laboratory tri-axial tests of rock. The theoretical research achievements are applied to the practical engineering and a quantitative prediction method for slope disease is proposed. Several approaches of solving the two problems of determining the slope pressure on stabilizing structure and appropriate anchorage angle in the anchor rope engineering are presented. While theoretical research is made, the application of the theory to practical engineering and checks for the legitimacy of the theoretical results compared with practice are important part in this thesis . The following is the research contents.(1) Based on the collection and sort-out of a large number of engineering examples, the classification of slope geological structures has been done. The structures can be classified into six basic types, i.e. base, stratiform, eyeball-like, blocky, loose crumble, and isotropic-like slope geological structures.(2) The basic types of the slope damage are summarized. According to scales and formation mechanisms of damage slopes, the damage can be classified into 5 basic groups, i.e. rock-fall, collapse, slope fall, slide, and toppling. According to the development history of the damage slopes they can be classified into two groups, reviving old damage slope and new damage slope. And according to damage scales, the damage slopes can be classified into four groups, such as mountain deformation, landslide deformation, slope deformation, and hill slope deformation.(3) Affecting factors of the slope damage are described. And discussion on the domination of the damage by slope geological structures, and important effect on the damage caused by the ground water and excavation process is centered.(4) the geomechanics method of damage prediction for high slope including determination of regional structure background by the geomechanical investigation of the fracture and macro-geological judgment of the slope damage by investigation and analysis of limited stability slope. Practical applications of the geomechanical method of the damage prediction for high slope to damage prediction are described in the three aspects, geomorphy analysis of slope, geomechanical investigation andanalysis of fracture, and geomechanics of fracture , which are complementary to each other. And the macro-geological judgment of space damage prediction in space of high slope is described by three aspect, judgment method, occurrence segments and structure cause of the limited stability slope .(5) Based on the methods of determination of sliding planes which have been summarized, a new fix-point approach is proposed, which combines geologist's experence judgment and the random search technology of sliding planes. This new method has more practical meaning in judgment of possibility of occurrence of sliding planes in slope with pre-existence of old sliding planes.(6) Based on the fix-point approach, a method of determination of appropriate location for anti-slide pile is further presented. First it is assumed that a lot of locations of anti-slide piles are considered. For each location the fix-point safety factor can be calculated. If the fix-point safety factor is greater than the design safety factor, the location is taken as a appropriate pile location. Then the optimum pile location is determined under consideration of both magnitude of anti-slide thrust and pile size. A pratical engineering of zhangjiaping slide is taken as an example in order to introduce the fix-point method for the application to determination of select type of slope protection structure.(7) According to former research results and characteristics of stress-stain curve in tri-axial test of soft rock, statistical constitutive relation of the rock damage based on the Mohr-Coulomb Criterion is derived, This constitutive model can be fit in with the stress-strain curve in tri-axial test of soft rock under different confining pressure.(8) In term of analysis of displacement and stress field in slope a new method of calculation of the local safety factor in slide zone inside slide is proposed. The local safety factor in slide zone depends on the directions of displacement vector during sliding, and provided the component of the element stress in the direction of the displacement vector is obtained the local safety factor can be estimated.(9) In term of the powerful embedded FISH language of FLAC3D program, the interface program of stress correction based on Mohr-Coulomb model is developed by the platform of FLAC3D program. Application of statistical constitutive model for rock damage dirived above to numerical calculation, and combined with strength reduction method the locations of slide planes in slope failure can be determined. The combination of the definition of slide zone local safety factor with thedetermination of slide planes can not only predict the final locations of slides in slope failures and global safety factor, but analyse the characteristics of stress field in different deformation stages. In addition, the method can determine the trends of evolution process of slide zone local safety factor, and then the failure mechanisms of slopes can be judged in order to guide engineering design. Feasibility of this method is checked by calculations in practical engineering examples.(10) Implementation procedure for each method of four methods of damage prediction are synthesized, and each of the four implementation procedure and relation among the methods are expounded in detail. Combination of different approaches is applied to prediction of the slope damage.(11) Through the large scale geo-mechanical model tests, development pattern for two kinds of damage of slope geological structure, which occurred commonly in sites, is predicted. Problems in practical engineering are solved. And compared with results of theoretical calculation, the legitimacy of theoretical calculation method for prediction of damage is checked.(12) Based on the fix-point approach, the theoretical calculation method of distribution form of the anti-slide thrust of anti-slide pile is proposed. Both the different lithology of sliding mass and the different geometric shape of the slope are taken into account in this method. Without any assumption, the distribution of anti-slide thrust can be determined by calculation in term of the method.(13) The approach of determination of earth pressure in support system consisted of anti-slide pole with pre-stressed cable and frame work with pre-stressed cable, which is quite commonly used in engineering is discussed. In this method, it is assumed that the sliding mass is rigid, when the slip of intack rock slope occurs, and the earth pressure is estimated by comparison with the displacement of the supporing structure.(14) It is suggested that in design for foundation beam with pre-stress cable, no relative slide between foundation beam and rock should be taken an pre-judgment criterion in order to provide maximum slip-resisting force. And determination of the appropriate anchoring angle for foundation beam with pre-stress cable is discussed.