Comparative Study On Excavation Schemes Of Retaining Walls For Deep Cutting Slopes

The stability of deep cutting slope is an important condition to ensure the the subgrade complete its function,and is also the main content of subgrade design.Inevitably there will be a large number of deep cutting slope in the high grade railway construction in hilly and mountainous areas.The destruction of deep cutting slope is a serious threat to the safety of high-speed train,which causes huge losses to the country and the people’s economy,at the same time,destroys the environmental landscape and ecological balance.In the slope treatment,there are many measures can be selected,the development of pile-sheet retaining wall is in the landslide prevention and control project of the anti-slide pile foundation up,Now the pile-sheet retaining wall in slope supporting engineering application more and more extensive in the slope treatment。In this paper,the stability of the deep cutting slope and the different retaining structures types are analyzed.The main contents are as follows:(1)The regional geological environment of the study area was analyzed.Including topography,lithology,geological structure,hydrogeology and meteorological characteristics,The geological environment conditions and the basic characteristics of deep cutting slope are expounded.(2)According to the physical and mechanical indexes of direct shear test and engineering geological exploration,according to the characteristics of the study area,put forward two kinds of pile wall retaining scheme,The stability of the slope under the two schemes of high retaining ratio + less excavation,double line short retaining and multi excavation is evaluated by transfer coefficient method,and the residual sliding force of each slice is calculated.(3)The slope takes 1.15 safety factor,and calculates the residual sliding force of the pile at the leading edge of the slope by the transfer coefficient method,.The residual sliding force at the front of the slope is determined,in scheme I(high retaining + less in excavation),Calculated based,the thrust of the deep cutting slope to the pile is 950.7kN/m,cantilever section to meet the requirements of the force.The section size of the pile is 2.0m * 3.0m,the length of the pile is 22 m,and the distance of the pile(middle to middle)is 6m,which requires a total of 26 piles;In scheme II(double low retaining and more in excavation),according to the calculation,the thrust of row piles of deep cutting slope is 650.8 kN/m,the pile section size is 2.0m * 2.5m,the length of the pile is 15 m,the distance of the pile is 6m(middle to middle),a total of 26 piles;The thrust of the deep cutting slope is 337.1 kN/m,the section size of the pile is 1.5m * 2.0m,the length of the pile is 13 m,and the distance of the pile(middle to middle)is 6m,which requires a total of 18 piles;(4)From the design idea,structure,construction cost and the degree of difficulty of the two schemes are compared.The comparison results show that the amount of earthwork,the scheme I 80127-52332=27795m3 less than scheme II earthwork,but the total project cost more than 945156 yuan,the cost of the project more than 18.3%.Scheme II has great advantages in structure form,construction cost and difficulty of construction.(5)The two retaining schemes are divided into five steps,and the stress,strain and mechanical characteristics of the five steps of the two schemes are analyzed and studied in depth by using the finite element software FLAC3 D.The results show that the slope of the slope is smaller,the X-displacement of the slope is smaller and the safety reserve is greater.