| This accumulation body located outside of the Erpingzi sinkholes Gully mouth,the total square of about 2125.5×104m3.Since the accumulation of a large body size,riverside high steep slope, and the next diversion tunnel inlet,Jinping II Hydropower Station dam is low,less storage capacity,the accumulation slope instability once total or partial,it may cause blocking secondary geological disasters,river, reservoir sedimentation and swell,but also a serious threat to the safety equipment and camp personnel located on the Erpingzi.Therefore,the Outside of the ErPingZi Accumulation basic characteristics,genetic mechanism and stability study of security operations to protect the project is necessary.In this paper,Erpingzi Accumulation of body Stability research topics of Jinping II hydropower as the basis,a comprehensive understanding of the mechanism of slope stability and the statusquo analysis of the causes accumulation body on the basis of the stacked body by field surveys to collect drilling Engineering and geophysical data,combined with laboratory analysis, the accumulation of body shape characteristics,boundary conditions,material composition and structural characteristics of the material studied.Analysis of the bulk formation mechanism and geological macro discriminant analysis,physical simulation test,limit equilibrium and numerical analysis,systematic study of the stability of the stacked body in different regions, to provide geological basis for the safe operation of Jinping hydropower project.The contents and results are as follows:(1)The study of natural and geological conditions of the study area.Research on climate zone belonged to West Sichuan Plateau,the Yalong River is the largest in the region,the region into a severe cut high- in the mountains,the natural landscape can be divided into two units:the eastern edge of the Tibetan Plateau region and erosion erosion nagorye construction of high mountains,exposed strata are mainly Triassic(T1, T2 z, T3) formation and the Quaternary loose deposits,structure is relatively complex,development of four faults,four joints and groundwater mainly Quaternary loose bulk pore water and the base layer rock fracture water,karst water three types of fault activity in the region is weak,low-frequency earthquakes.(2)Basic characteristics of the stacked body.The accumulation body form longitudinal whole from slow to steep,topographic control on overall morphology from top to bottom by wide narrow,the 1# gully is left bounded,the 2# gully is right bounded,trailing edge for ER Ping Zi retarding trailing edge,leading edge reaching the Yalong River,consisting mainly Pleistocene and Holocene Quaternary rockfall deposit, and fluvial,underground water level generally deep buried between 14.0m to 142.0m. According to the composition and structure of matter and the accumulation body is divided into A, B two regions, wherein A zone can be divided into A1, A2 two sub-regions.(3)Mechanism of Accumulation Cause. The field investigation and analysis, the genesis of the main factors controlling the accumulation of river incision on both sides of the slope leading to the formation of an effective free face lift, mudslides erosion cause toe volley,slope generating tension cracks under the action of gravity, fault F26 structure and faceted further reduces slope stability,analyze the evolution of accumulation body,A district accumulation body is mainly composed of fell into the ditch road on both sides of the collapse slide accumulation body and ER Ping Zi platform trailing edge on the left side of the colluvial accumulation body,area B stacked body mainly on the left bank slope at the Yalong rockfall integrated supergene effectiveness of action arising.(4)Stability Analysis of accumulation.macro discriminant analysis using geological,A1 zone accumulation slope overall stability under natural conditions, instability and failure to locally-based small-scale collapse,A2 area better overall stability,mainly by sinkholes debris flow erosion,area B accumulation slope under natural conditions is stable, unstable failure to local small-scale slide(collapse) the collapse of the main;physical simulation analysis,Sinkholes debris flow to the stability of the stacked body is mainly reflected in the phenomenon of pull grooves on the surface of the body accumulation of Quaternary loose material and the trench sidewalls pull crack occurs toppling failure, Through the limit equilibrium calculation, the overall stability of A1 slope is better, but the front steep terrain stability slightly lower, a basically stable state, although to meet safety standards, but safety is lower; the overall stability of A2 is better, but the upper part of the terrain is steep at the slope is in stable state and the conditions in the day, heavy rain condition in the limit equilibrium state, there is instability dangerous earthquake condition its safety margin is not high; B accumulation of small thickness, various working conditions are meet safety standards, but the heavy rain condition safety reserves slightly lower; by FLAC3 D numerical simulation analysis of stress distribution is mainly affected by the accumulation of body gravity stress, with general the level of accumulation of body stress distribution due to the different parts of different thickness, the stress size and distribution are different; the main deformation stress in weight To focus on the steep slope of the site, by the impact of micro topography. |
PDF Full Text Request