Treatment Methods and Settlement Simulation Calculation of New Road Foundation in Collapsible Loess Areas
In order to prevent the instability of high fill subgrade caused by loess subsidence,the filling subgrade of the K12+220～K12+860 section of the G8513 Expressway was taken as the research object.The self weight subsidence amount and total subsidence amount were used to determine the type and grade of loess subsidence,and the foundation was divided into sections A and B.A treatment plan for collapsible loess foundation has been developed based on principles of safety,economy,and ease of construction.For section A,it is pro-posed to use the dynamic compaction method,which should extend beyond the foot of the slope by 3.0 m.The single click compaction en-ergy should be 1 200 kN·m,and the arrangement of compaction points should be an equilateral triangle.The center to center spacing of the compaction points should be1.2～2.0 times the diameter of the compaction hammer.The compaction should be carried out in three stages:main compaction,secondary compaction,and full compaction.When the average settlement of the last two compaction is less than 50 mm,the compaction can be stopped.For section B,it is proposed to use lime soil compacted piles with a pile diameter of 0.5 m and a pile spacing of 1.2 m.The holes will be drilled using the sinking method,and the piles will be arranged in an equilateral triangle shape.A 40 cm lime soil cushion layer will be laid on top of the piles.Subsequently,a model of high fill subgrade was established using numeri-cal calculation software to simulate its settlement after treatment with lime soil compaction piles.The calculation results showed that the longer the lime soil compaction piles,the smaller the post construction settlement.When the pile length is greater than 8 m,the post con-struction settlement change is not significant,so the optimal pile length for comparison should be 8 m.
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NSTL
万方数据
维普
