Application Research On Compaction Pile And Dynamic Consolidation Treatment Method Of Collapsible Loess Foundation In XinJiang Expressway

Collapsible loess is widely distributed in many highway reconstruction and expansion projects in Xinjiang.In highway construction and project management,if we can not take effective measures to strengthen the foundation to reduce the collapsibility of natural foundation,it will have adverse effects on the quality of the project and the traffic safety during the operation period.Based on a typical project,this paper uses the control variable method to test the compaction effect of collapsible loess foundation and static load test of lime soil pile through different lime soil ratio,pile diameter and pile spacing,and obtains the test data of pile bearing capacity and foundation settlement.Through the analysis,the influence law of lime soil ratio,pile diameter and pile spacing on compaction effect is obtained.Combined with the theoretical analysis and comprehensive analysis results of test compaction test,the quality control standard for collapsible loess foundation with large pore and silt content accounting for 80% in Yili area is proposed.When "δ s < 0.015" is used as the actual effect of judging whether the Loess body is collapsible or not,the compaction degree and hammering number can be used to evaluate the dynamic compaction effect.The research shows that: because the collapsible loess in Xinjiang has the special properties of loess like soil,when the compaction pile method and dynamic compaction method are used to treat the collapsible loess foundation of expressway,while paying attention to the detailed management of construction quality,the control indexes of foundation bearing capacity and collapsible coefficient must be selected to evaluate the compaction effect after the construction of compaction pile method.For the special loess in Yili area,the compaction degree,the number of heavy dynamic penetration hammers and the characteristic value of foundation bearing capacity obtained from plate load test are used as the quality acceptance standards of dynamic compaction foundation.Taking the coefficient of collapsibility as an auxiliary parameter,the construction quality of foundation treatment can be guaranteed and good treatment effect can be achieved through continuous improvement of working procedure and design.