软土的固结状态对抗剪强度影响的研究

Research on the Impact of the Soft Soil Consolidation State on Shear Strength

排水固结法处理软土地基的主要目的是加速软土的排水固结,保证路堤填土加载与地基土抗剪强度的增长相匹配,减少工后沉降。为此,需要研究软土固结度对抗剪强度的影响,研究成果为区域性软基的设计和施工提供依据。通过直剪试验和单向压缩固结试验,研究了固结压力为100kPa时,软土抗剪强度及抗剪强度指标与固结度之间的关系。试验结果表明:当固结度小于20%时,固结度的变化对抗剪强度影响不大;当固结度大于20%时,不同法向应力作用下抗剪强度随固结度的增大而增大,基本上呈线性的增长关系;在同一固结度下,增大法向应力对抗剪强度的增加影响较小;区域软土内摩擦角随固结度的增加,总体上有所增加,在增加的过程有起伏,规律性不明显;黏聚力随固结度的增加而增大,当固结度较大时,增加较明显。

The main purpose of the drainage consolidation method of soft soil foundation is to speed up the soft soil consolidation,ensure embankment fill loading and the growth of the foundation soil＇s shear strength matching and reduce the post-construction settlement.Therefore to study the effect of soft soil consolidation degree against shear strength is important,and the research results can provide the basis for regional soft foundation design and construction.The direct shear test and unidirectional compression consolidation test are conducted to study the relationship between soft soil shear strength,shear strength index and degree of consolidation when the consolidation pressure is 100 kPa.The test results show that when the degree of consolidation is less than 20%,change of the degree of consolidation has a little influence on shear strength;when the degree of consolidation is more than 20%,different normal stress shear strength increases with the increase of consolidation degree,and appear as linear growth relationship,under the same degree of consolidation,increase of normal stress has a minor impact on the increase of shear strength;regional soft soil internal friction angle on the whole increase with the increase of degree of consolidation,and there are ups and downs in the increase process,the rules is not obvious;and cohesion increases with the increase of degree of consolidation,when the degree of consolidation is larger,there is more obvious increase.