A Research On Formation Mechanism Of Gently Inclined Bedding Rock Landslide

Slow dip bedding rock landslide is a special landslide type in slope engineering.There are many gentle dip formations in the eastern part of Sichuan basin.The dip angle of rock strata is mostly 10 to 20 degrees.Because of the type of the slope rock angle is small,from the previous scholars on the study of this type of landslide and the traditional geological point of view,this type of rock slope is a massive failure,but in recent years,in the extreme condition of strong rainfall,the landslide mass of large area Sichuan area events are It is often seen.as of September 16,2011.~18 caused by heavy rainfall in Bazhong Nanjiang 1000 slope instability,including hundreds of millions of cubic meters of this type of landslide,causing great damage to property.At present,there is no unified and clear conclusion on how the slow dip rock slide is produced from 10 to 20 degrees.The existing studies suggest that the formation of the landslide cracks are filled with water after the hydrostatic pressure and the bottom surface uplift pressure is the result of inclined rock layer along the driving force of the occurrence of landslide,but through the discovery of multiple rock landslide investigation in Nanjiang County,have not formed the trailing edge of landslide filling head pieces,with mudstone or even natural the shear strength of slip soils of typical landslide stability calculation results also shows that the landslide is difficult to occur instability in the comprehensive effect of water pressure and uplift pressure.Therefore,it is necessary to study the formation mechanism of the gently inclined bedding rock slope.Based on the investigation of the landslide Chenjiawan on engineering geological survey and Analysis on the formation mechanism of the landslide,and then the representative section of Lizheng software Chenjiawan No.1 landslide stability calculation,according to the calculation results,the Chenjiawan landslide stability evaluation.The sensitivity of the landslide is analyzed by orthogonal analysis.On the basis of changing the thickness of rock,and in accordance with the different combinations of strata thickness,the rock slope is divided into three types: rock slope and rock layer thickness,thin interbed thick strata rock.The analysis then using Lizheng software for stability evaluation of the three different thickness of the rock slope deformation and failure mechanism.At the end of this paper,the prevention and control scheme and suggestions for the landslides of Chen Jia Wan are put forward.The main research work and achievements of this paper are as follows:(1)the representative of Chenjiawan No.1 landslide slope stability calculation,the results show that the Lizheng software landslide is in a steady state under gravity conditions,in(rain + weight)in the critical state of the state.(2)for the sensitivity analysis of factors Chenjiawan No.1 landslide that of internal friction angle and cohesion of the earthquake and landslide stability is highly significant influence on the stability of the landslide location of underground water level significantly,soil heavy influence on the landslide stability in general.(3)the landslide hazard prediction and prevention suggestions on Chenjiawan: the landslide belongs to progressive rock landslide,sliding and once in bedrock cracks in loose gravelly pore body in water filling and widening,will increase the sliding body pressure and water pressure,the sliding body forward edge surface slip failure.Once the whole landslide is unstable,it will seriously threaten the lives and property of 9residents and 48 residents of the trailing edge of the slope.At the same time,the landslide area is close to the traffic main road of the town.Once the landslide is unstable,it will cause traffic jam and the loss will be more serious.(4)based on the numerical simulation of the landslide and the analysis of its genetic mechanism,a control plan combining anti slide pile + retaining plate + drainage facilities is put forward.To further improve the stability coefficient with drainage measures(based on the original water drain on a drainage ditch),and set the anti slide pile and retaining plate to increase the anti slide force,the retaining wall is slippery slope.(5)using numerical software to simulate three different layers of rock slope,the following conclusions are drawn:(1)for the slow dip bedding rock slide,the lower soft layer is located on the layer of fourth layers of soft rock(mudstone)layer.Change of strata thickness and has no effect on the deformation and failure mechanism,the deformation and failure of landslide is weak layer deformation and failure occurs first,upper strata and overburden displacement along the shear weak level front surface,until completely deformation and failure,namely sliding tension failure.(2)On the whole,the stability of the landslide will also increase when the thickness of rock is increased.When the thickness of rock is increased within 0.05-1m,the safety factor will increase slowly.When the thickness of rock layer is huge,the safety factor will increase obviously.That is,when the thickness of rock layer increases in the thin layer and thick layer,the contribution to the stability of landslide is low.When the thickness of rock layer increases in the thick thick layer,it will contribute to the stability of landslide.(3)for the bedrock landslides of this kind of soft and hard rock interbedding,the greater the difference between the thickness of the two lithologies,the more unfavorable to the stability of the landslide.