Under Conditions Of High Earthquake Steep Rock Slope Collapses And Dynamic Response Characteristics Of Rock Pile Toe

"5.12" Wenchuan earthquake triggered a lot of geological disasters such as landslides, avalanches, landslides, resulting in significant harm. Because of the strong earthquake cut the role of the river, is widely distributed with high steep rock slope. Development of structural surface slope, rock fragmented, prone to strong earthquakes in the unstable failure. Bandy Bay ramp would fall into that slope:the upper bedrock towering steep, loose lower part of the pile, under earthquake bedrock collapse occurred, while the lower part of the body has also undergone a loose accumulation unstable failure. In this paper, for the bandy Bay ramp-site investigation, the earthquake wave data collection based on the discrete element numerical simulation software3DEC and finite element numerical simulation software bedrock collapse and loose accumulation of power FLAC3D response characteristics analysis, mainly on the the following understanding:(1)Under the force of the earthquake, the destruction of both the occurrence of instability and collapse the pile slope instability and failure of a special occurrence, possible accumulation body in three forms:1) the role of seismic waves by a single loose accumulation instability leads to destruction;2) seismic forces and work together blocks of rock collapsed in shock loose accumulation leads to instability and failure;3) the seismic forces and the collapse of the rock heap block containing a common cause instability loose accumulation of damage.(2)Bandy Bay top of the slope surface bedrock structure and development, collapse under the earthquake occurred. Calculated bandy Bay top of the slope bedrock level seismic acceleration:a=0.7894m/m2≈0.07894g, earthquake peak acceleration of less than0.1g, reached the collapse occurred condition. Meanwhile, the slope seismic acceleration magnification n≈1.37, similar to the level of throwing motion occurs when judged earthquake.(3) The toe of the pile when the earthquake generated by the earthquake loosening. The calculated accumulation under seismic stability coefficient1.0472, larger than a critical value, can be seen in the earthquake, the pile unstable failure did not occur, but had some permanent displacement.(4)Bandy Bay slope steep slopes, undulating terrain, steep slopes tend to have developed upper body with a certain width and depth of the slope of the tributary, while the collapse of basic and primary source of high bedrock collapse along the direction of the front-end development within these factors are collapsed block of rock loose accumulation rapid movement to create a good path, coupled with the new accumulation body stacked seismic zonation determine bandy Bay ramp is preloading force and collapse in an earthquake rocks the block co-instability occurs under the action of destruction.(5Collapse of the entire process using the discrete element numerical simulation software to simulate3DEC while Shijiawenchuan Ms8.0earthquake mainshock stations-Li County wooden card station measured seismic waves calculated results show that under the action of seismic waves, the first bedrock slopes dislocation structure occurs along the surface and separated into many different sizes of rock blocks, sustained earthquake, will rock to slip free surface, the first part of the rock block out the weight and the occurrence of cardiac collapse, then most of them have the same rock mass displacement of the heart out of the body weight, similar to a large area of flat throwing motion collapse occurred.(6)Using the finite element numerical simulation software FLAC3D natural state, respectively, seismic conditions, earthquakes+preloading conditions of accumulation body simulation results show that:Under natural conditions, the slope of the maximum principal stress distribution was significantly affected by the gravitational field, the magnitude and depth of the overall proportional distribution is more uniform, while shallow slope near the surface is adjusted to the slope parallel to the minimum principal stress directions within the slope is generally horizontal direction, while the slope near the table adjusted to near vertical slope; under the earthquake, the main stress direction has undergone a drastic change; strain concentrated mainly in the edge of the rock at the junction and the junction of the foot of the pile; under natural conditions, the amount of displacement slopes little affected by the earthquake, displacement mutated; displacement of the rock heap load applied under seismic conditions, limited only by the accumulation of displacement than the earthquake occurred bias, with the continuing role of the earthquake, increasing the deviation large, instability occurs until the final destruction of the pile.