Study On Stability Evaluation And Treatment Measures Of Toppling At Erguxi

This paper takes Shiziping Hydropower Station Reservoir area Er Gu Xi toppling deformation of slope as the research object,by collecting the original geological and historical data,using the slope surface exploration,drilling and adit catalog and on-site monitoring means of investigation,by faults,unloading fissures,weathering degree limit,the boundary line of underground water on the slope of sections of the field of qualitative,also based on combined with adits on-site RQD measurement and rebound testing and sampling of indoor rock mechanics experiment on slope comprehensive regionalization;by different evaluation methods of rock mass quality of dump slope each section of rock mass quality evaluation,combined with different experience estimation method and Indoor rock mechanics experiment,it can be concluded that the mechanical parameters of rock mass;through field investigation and numerical simulation means,toppling deformation body in different storage conditions on deformation failure characteristics,loss of stability and stability analysis and evaluation,finally put forward reasonable slope treatment measures implementation of the program and numerical simulation to study the treatment after reaching effect.Several main conclusions are as follows:(1)Erguxi deformation slope are Quaternary loose deposits cover,only local sporadic exposed bedrock,covering layer from top to bottom can be divided into gravelly soil,with a piece of broken gravel soil,bedrock metamorphic sandstone of Middle Triassic miscellaneous brain Valley Group T2 z clip phyllitic slate,Zhuwo group(T2zh)thousand coins like slate and metamorphic sandstone interbedded,bedrock overall is broken,toppling rock mass deformation signs are obvious.(2)In the 2008 "5.12" Wenchuan earthquake,the two ancient Creek 1# tunnel appear small cracks,in 2011 to 2012 rainy season continued to be strong rainfall,the two ancient Creek 1# tunnel cracks continue to focus on the development of and tunnel through the reinforcement treatment after recovery,2013 may Shiziping Hydropower Station started the second impoundment and October 2013,in rainy season rainfall and reservoir second phase water storage effect of water immersion,ancient second XI slope edge cracks of sustainable development into basically through the trap,the two ancient Creek 1#,2# tunnel Again cracks,two ancient Creek bridge also appears to deformation and failure,causing G317 changing state line road is temporarily interrupted,November 2013 reservoir water level began to decline,then the slope deformation convergence slowed down,basically stable,during the rainy season in 2014.The deformation of the slope and gradually began to change,slope deformation and the reservoir water level,rainfall direct correlation.(3)Development of downstream 2# transverse highway tunnel deformation.A2 did not appear,imports of tunnel deformation and deformation on the basis of topographic and geological conditions and deformation characteristics of different,Gu Xi body divided into strong deformation zone a weak deformation zone B.Strong deformation zone a and can be divided into three sub regions,A1 District obvious signs,the upstream boundary cracks in the ancient river 1# upstream near the downstream edge crack is located in the ancient river bridge on the left bank of the bridge side,the trailing edge of the transverse crack zone signs of obvious upstream boundary cracks along the two ancient Creek 2# outside of pavement upwards,extension of the downstream boundary cracks in the ancient river tunnel entrance to cave,trailing edge boundary is not clear,no cracks,the leading edge of highway retaining wall shear fracture,2 # tunnel floor wrong uplift,the top of the side wall arch shear deformation of obvious.A3 area although the overall deformation signs less,but it is located between A1 and A2 zone in the upper,directly affected by the control stability of these two areas.(4)according to the analysis of measured data and engineering experience analogy to establish the classification system based on,combined with structure as revealed by the study area three adit status and limited data,and the actual situation of the deformation,rock mass of slope of two ancient Creek,by toppling deformation degree and deformation control structure of the bottom boundary,from the inside outward would divided into:(A)the original stratigraphic region,(B)weak dumping deformation zone,(C)strong dumping area,(D)fall covering area.By using the RMR method of toppling deformation of slope rock mass of each section of the rock quality evaluation,rock mass quality is divided into four grades,from falling nappe zone to deep rock mass quality is very poor(V)transition to good rock(II).And the Own criteria combined with RMR method to select the mechanical parameters of rock mass,in order to ensure the reliability and scientific of the evaluation of rock mass quality and the selection of parameters.(5)Through the analysis,it is known that the dumping slope in the reservoir normal water level,prone to slope instability and collapse.The flow and wave scour,reverse slope or hole in weight Cover loss bounds for 2540 m lumps of rock caving or collapsed.At the highest water level is below the water level of rock and soil mass will be because of the physical and mechanical strength decreased and increased buoyancy effect and edge cut through the deformation body,along the front cover slip steady decline.With reservoir water level rising,the leading edge of sliding resistance ability will be reduced,may make the accumulation body appeared successively receding instability destruction,of course also may when the reservoir water level rises to a certain height,due to the accumulation of body front of sliding resistance capacity decreased,thus appear along the base boundary integral instability destruction.The reservoir water level drop.The gradual progressive decline of the slope will be the instability mode.(6)through the Flac3 D numerical simulation of two ancient river dumping slope before impounding water before the natural state of slope can maintain overall stability,only the top local tensile stress characteristics;shallow and strong dumping areas for the displacement and strain are greater than the weak dumping area,although the amount is very small;the slope in normal water although,the whole slope can keep stable,but the leading edge of the slope to the slope displacement and strain accumulation were increased,and the plastic area also has strong dumping area along the bottom boundary to the upper slope expansion trend,shallow and strong dumping area of displacement and strain are greater than the weak dumping area,that after impoundment by water,the slope of rock and soil softening pore water pressure and groundwater level caused by the impact,leading a significant accumulation of body deformation,and will produce shear instability breaking down Slip form through the valley was significantly greater than that in the bottom boundary of bad;further uplifted to the highest water level,slope front and the toe of pile displacement and stress variables are compared with normal water increased sharply,and the plastic zone along the strong dumping area through to the slope edge cracks site,shallow and strong dumping area of displacement and strain Dudu weak dumping area,it means that the impoundment uplifted to the highest slope not only the foot slope rock and soil softening and deformation to the direction of shear instability destruction,is also reflected in the slope body within the plastic zone,the slope will be along the strong dumping area bottom boundary surface,generate traction type of instability failure.(7)according to the engineering geological conditions,dumping two Gu Xi deformation body structure characteristics of rock and soil and slope under normal water and the highest water after the stability condition,puts forward two kinds of solutions that the program intends to adopt a row anti slide pile retaining body is arranged in the front deformation of the highest water level above,due to the shallow surface the front pile is thick,can be appropriate for excavation slope or increasing the pile length and section size;scheme two intends to load back pressure in the front at the foot of the slope deformation body,the formation of anti sliding embankment,the loading height is higher than the highest water level,so that the national highway G317 section can pass from the pile of the carrier,and the surcharge in vitro exposed slope slope should be dry rubble and concrete.Finally the scheme selection of two foot compared to get the most reasonable counter pressure.