路堤下等应变复合地基的固结分析

ANALYSIS OF CONSOLIDATION OF EQUAL-STRAIN COMPOSITE GROUND UNDER EMBANKMENT

路堤下等应变复合地基固结沉降时,桩间土承担的荷载向桩体转移,桩土总应力不断变化,超静孔压增减量不等于有效应力增减量。考虑桩土总应力的变化、竖向排水体的压缩和孔隙水压力、桩体的排水性能、桩与排水体的距离等对复合地基的固结产生的影响。推导考虑桩体排水性能、桩土荷载转移、排水体压缩性和井阻的路堤下复合地基孔压、固结度、桩土应力比的解析解。固结分析表明,不透水桩可以加速地基固结,透水桩可能减缓固结,复合地基固结的快慢受桩身固结系数影响很大,高固结系数桩复合地基固结度大于小固结系数桩复合地基。

The load on the soil is transferred to piles, and the total stresses of pile and soil changed when the equal-strain composite ground under embankment is consolidated. The change of excess pore water pressure isn＇t equal to the change of effective stress of composite ground under includincy embankment. The influential factors of consolidation of equal-strain composite ground with piles, including total stress of soil or pile, compressibility and excess pore water pressure of vertical drain, permeability of pile and relative position of vertical drain and pile, are analyzed. The results of analytical solutions considering pore water pressure, degree of consolidation, stress ratio between pile and soil by which permeability of piles, transfer of load between piles and soil, compression and well resistance of vertical drains, is carried out. It shows that impermeable piles can increase the consolidation of ground but permeable piles maybe delay the consolidation; the consolidation of composite ground is highly influenced by the coefficient of consolidation of pile; the degree of consolidation of composite ground treated by piles with high coefficient of consolidation is larger than that with low coefficient of consolidation.