| The highway from Lin Xiang to Qingshuihe which local in Lin Xiang district and Gengma county of Lincang city in Yunnan province,is an important part of the planned highway from Kunming to Qingshuihe port.The mileage between K97 + 500 to K111 + 900 of this project is designed wiring along the southeast bank of Nantinghe river.Due to the multiple changes of the river course in the valley,the composition of the soil layer presents the cross-bedding of saturated powdery sand,silty clay,gravel and cobble soil and medium or coarse sand containing gravel,so the stratigraphic situation is very complex and changeable.silty clay and saturated powdery sand soil can cause engineering diseases including insufficient bearing capacity,large compressibility and nonuniform settlement.According to the characteristics of the soft soil foundation with complex sedimentary environmentin in Linqing highway,the engineering designer selected the dynamic compaction scheme to consolidate soft soil foundation.Although dynamic compaction method has been widely used,its evaluation of consolidation effects is still being studied.In the previous research,the effects of different stratum conditions were often neglected in the evaluation of the consolidation effect.Therefore,evaluating and analyzing the effect of dynamic compaction systematically under different stratum conditions based on the field measurement data is of great practical significance.This paper relies on experimental section of soft soil foundation consolidated by dynamic compaction in Linqing highway,using in-situ testing,laboratory testing,field monitoring and numerical simulation to study the effects in dynamic compaction for reinforcing soft soil foundation with complex sedimentary environment of floodplain in Linqing highway as well as the influence of different working conditions on it.The main research results of this paper are as follows:1.Through monitoring and analyzing the change of pore water pressure,earth pressure and stratified settlement of soils,the variation law of pore water pressure,the growth law of effective stress and degree of consolidation,as well as the development law of settlement at different positions of subgrade are obtained.2.Through the standard penetration test and static cone penetration test,the blow count of SPT,the basic bearing capacity and modulus of compressibility of the foundation soil at different depths before and after the consolidation are calculated.Based on its lifting amplitude,the effective consolidated depth is analyzed and evaluated.3.The finite element model is established to simulate the response of foundation soil in the process of dynamic compaction.The dynamic compaction load and the stratum structure is changed to simulate different dynamic compaction construction conditions,the reinforcement effect of foundation soil under different dynamic compaction construction parameters and different stratum structure is analyzed,and the rationality of strengthening scheme of Linqing highway is evaluated which provides a reliable theoretical basis for the dynamic compaction of soft soil foundation in the sedimentary environment of floodplain. |
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