黄土自重湿陷下限深度确定方法研究

Study on determination method of the maximum depth of loess collapsible under saturated self-weight stress

鉴于室内试验确定的黄土自重湿陷下限深度与野外实测值存在明显差异,基于饱和状态下黄土的似先期固结压力就是湿陷起始压力的观点,以陕西渭北黄土为研究对象,提出了一种新的判定自重湿陷下限深度的方法.首先利用浸水状态下黄土的固结试验测定了黄土的似先期固结压力,其次用似先期固结压力方法确定了湿陷起始压力,最后通过湿陷起始压力与饱和自重压力的对比分析进行自重湿陷性判定,确定了自重湿陷下限深度.现场试坑浸水试验结果表明利用本文所提出的方法确定的黄土自重湿陷下限深度值与实测结果基本一致,验证了方法的有效性.研究成果可以为黄土湿陷起始压力、湿陷敏感性等问题的深入研究提供借鉴.

The maximum depth of loess collapsible under saturated self-weight stress determined by laboratory test shows obvious difference when compared with that measured in the field experiment.Based on the viewpoint that the pre-consolidation pressure of loess in saturated state is the initial pressure of collapsibility,this paper takes the loess from Weibei in Shaanxi Province as the research object,and proposes a new method to determine the maximum depth of loess collapsible under saturated self-weight pressure.First,the pre-consolidation pressure of loess is measured by the consolidation test of loess under water immersion.Then,the initial collapse pressure is determined by the pre-consolidation pressure method.Finally,the self-weight collapsibility of loess is determined by the comparative analysis of the initial collapse pressure and the saturated self-weight stress,determining the maximum depth of loess collapsible under saturated self-weight stress.The results of field immersion test in test pits show that the maximum depth of loess collapsible under saturated self-weight stress determined by the proposed method is consistent with the measured results,which verifies the effectiveness of the method.The research results also provide references for the intensive study of issues like the initial collapse pressure and collapsibility sensitivity of loess.