Numerical Simulation Study On The Characteristics And Formation Mechanism Of Zonal Disintegration Of Epigenetic Reformation Of Rock Slope

In the process of the surface reformation of the rock slope,there are some structural planes,such as medium dip angle crevice,etc..In the valley area,it is often found that the fracture?zones?are characterized by the the distribution of fissures in dense and sparse zones,such as zonal disintegration in the deep rock mass engineering.In this paper,the Songta hydropower station in Nu river as an example,the structure of rock mass in dam area,especially the basic data integration of a large number of unloading cracks on the statistics,we found that the slope in shallow rock fracture has such obvious regularity: the uneven spatial distribution.Therefore,the characteristics of slow crack in the slope were sorted out,and the characteristics of surface transformation and zonation of fracture were analyzed,combined with the macroscopic deformation signs and micro rupture mode of rock fracture,the theories related to the zonal disintegration phenomenon to reveal the rock slope shallow rock fractured zones the characteristics,and were simulated using the FLAC^3D software to demonstrate the development and distribution characteristics of corrosion crack,the main points are as follows:?1?There are a lot of fractures in the 100¹80m range from the slope to the slope in both sides of the slope,most of which are filled with debris and secondary yellow mud.This depth range is often referred to as the "epigenetic transformation zone" of the slope rock mass.In the surface of the slope,there is a spatial distribution inhomogeneity in the medium dip fractures:?1?On the wall of the adit,the distribution of the "slow,dense,sparse and dense" is shown in the middle of the tunnel,and the unequal degree of development of different elevation and slope.?2?The unequal degree of development of different elevation and slope.Low elevation "slow and dense",high elevation "steep and sparse",and low elevation fracture continuity is low?"dense and short"?,and high elevation continuity is relatively high?"sparse and long"?.And the fracture development degree of the right bank is obviously higher than that of the left bank.?2?Based on the two aspects of density and wave velocity,it is found that there is a good relationship between the two zones in the middle and slow dipping fractures,and the wave velocity curve is concave to the front and back sections.According to the mechanical properties of rock fracture deformation,in macro and micro these two aspects,the tensile shear fracture,fracture to coexist,and not separate deformation and failure,often in the form of a combination of a slow crack growth characteristics with the interval.The spatial combination model in the low angle fracture,intermittent reference Nu River Valley incised process and corresponding terrace elevations form,from the bottom up slope can delineate 6 inverted "A" shape of the extension,with inclined shallow valley inside,of which superficial part is slow,go deep extension steepens.According to the Zonation characteristics of medium dip fracture,namely the epigenetic reformation in zonal disintegration formation mechanism,explain its origin is intermittent cutting Valley discontinuity caused by adjusting the stress field,slow cutting when easy to form unloading fissures in large scale,fast cutting in rock mass can not form macro cracks obviously.?3?On the basis of qualitative analysis,the FLAC^3D strain softening model,numerical simulation of 3-3'selection of exploration line of valley cutting,cutting way based on the shape of the surrounding valley terraces which,in order to better approach the development process of cutting Nu River was intermittent.The relationship between the shear strain increment and the unloading crack is studied when the shearing speed changes.Found in the canyon,the shear strain increment?zone?and the stress field,displacement field,shear and tensile plastic zone position is consistent,are developed in the slow shearing,and shearing Valley speed intermittent correspondence.In the internal slope "jump out" migration,interval feature,and the rock fracture zone of discontinuous phenomenon is in good agreement,which proves the rock slope surface reconstruction of formation mechanism of zonal disintegration.In addition,the characteristic parameters??₁^P???of the model are analyzed:Within a certain numerical range,If the slope rock soil brittleness is stronger,or the softening deformation area and its surrounding rock strength difference is bigger,in the valley cut,the range of zonal disintegration is wider and the volume is higher,Vice verse.Through the study of this paper,it is hoped that it will be beneficial to the engineering geological analysis of the slope.