钢管注浆填土的剪切强度特性

Shear Strength Characteristics of Fill Soil Grouted Through Steel Pipes

为了了解钢管注浆后土体的剪切强度特性,以湖南株洲某建筑项目场地填土为例,开展了刚性体植筋、渗透加固两类直剪试验并进行原位剪切。室内试验研究了钢管植筋及渗透注浆对土体抗剪强度的影响,试验表明在刚性体植筋能提高土体的最大抗剪力至1.29倍,渗透注浆下土体的抗剪强度幅度与水泥掺量成正比。当水泥掺量为6%时最大抗剪力提高约2倍;原位剪切试验表明注浆后填土的最大抗剪力最高能提高9倍。由此分析钢管注浆加固新近填土的机理,除了浆液渗透增强土体抗剪强度、浆液本身及与钢管形成的结石体在填土中增加了土体的抗剪性之外,浆液对填土中的塑料袋、碎石、块石等物质的胶结作用也能极大地提高土体的抗剪强度。

The shear strength characteristics of fill soil grouted through steel pipes and conventional permeable grouting methods are studied throughout laboratory and field direct shear tests.This paper presents the comparative studies of grouted soils from a building site in Zhuzhou City,Hunan Province.The laboratory studies were concentrated on the grouting reinforcement through steel pipes and the cement slurry in the soil on the shear strength.The test results indicated that the grouting reinforcement can enhance the shear strength of improved soil to 1.29 times of the original soils.The shear strength of soil improved with permeable grouting was proportional to the cement content.When the cement ratio is at 6%,the shear strength of improved soil could be twice of the original soils.The field in-situ tests indicated that the grouting improved soil could have a shear strength nine times of the original soils.It is therefore concluded that,in addition to the grouted column formed through the grout operation and the soil shear strength improvement,the cementation of cement slurry between the boulders,gravels and other material could also contribute the shear strength increase.