吹填超软土固结特性试验分析

CONSOLIDATION PROPERTY OF ULTRA SOFT SOIL

为探讨吹填超软土的固结特性以及含水率与加荷比对次固结系数的影响规律,利用改装后的低压固结仪和常规的高压固结仪进行了分级加载固结试验。试验结果表明,正常沉积重塑土的固结系数随着固结压力的变化整体上呈现出逐渐增加的趋势,而超软土则表现为"S"型,即在低应力水平作用下,超软土的固结系数呈现下凹型增长;之后随着固结压力的增加,固结系数近线性增长,但增量比逐渐减小。与正常沉积重塑土不同,超软土的次固结系数随着固结荷载的变化存在峰值;加荷比对超软土次固结系数影响较大,较小的荷载增量可降低次固结系数;超软土及正常沉积重塑土的次固结系数均表现为随含水率的增加而增加。

This paper determines the consolidation characteristics and the influence of water content and load ratio on the coefficient of secondary consolidation of hydraulic fill ultra soft soil in Tianjin.A series of step-loading consolidation tests are performed on both ultra soft soil and remolded specimens using a modified oedometer with low applied stress and the ordinary oedometer.The results show that the coefficient of consolidation of the remolded specimens increases with the increasing consolidation pressure.But the ultra soft soil has a“S”shape of Cv-lgp curves.This“S”shape involves two parts divided by the consolidation yield stress（1 6kPa）.The one prior to the yield stress is responsible for concave increase while the other after the yield stress is responsible for linear increase with the decreasing incrementary ratio.Unlike to the normal sedimentary remolded soils,the coefficient of secondary consolidation of hydraulic fill ultra soft soil shows a peak value as the consolidation pressure is applied.Load ratio＆nbsp;had significant influence on the coefficient of secondary consolidation of hydraulic fill ultra soft soil.The smaller incremental load can reduce the coefficient of secondary consolidation.The coefficients of secondary consolidation of the ultra soft soil and normal sedimentary remolded soils are increased with increasing moisture content.