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Study of Static and Dynamic Penetration Test Capable of Applying Pore Pressure

施加孔隙压力的静、动贯入试验研究

基本信息

批准号：
61550359
负责人：
YAGI Norio
金额：
$ 1.28万
依托单位：
Ehime University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

项目摘要

A penetration test is a kind of a strength test for a ground. A strength of a soil depends on an effective stress. Strength tests must be carried out under two different effective stresses. Then, the penetration test in which an effective stress can be given to a point in the ground from a tip of a cone, is considered. Tests were carried out for the model grounds in the small tank. An arbitrary overburden pressure can be given to the model ground. Also influence of pore water pressure generated during penetrating to penetration resistance was investigated using the same tank.The results are as follows. 1) In the penetration test for the cohesive ground, the lower the penetrating rate is, the larger the penetration resistance is. The reason is that the strength of the ground around the tip of the cone approaches the drained strength due to dissipation of generated pore water pressure when the slow penetrating rate. 2) The static and the dynamic penetration resistances for the saturated ground is larger than ones for the dried ground when low void ratio, and vice versa when high void ratio. The reason is due to generated pore water pressure by dilatancy around the tip of the cone. 3) The static and the dynamic penetration resistances for sand ground when pore pressures are given to the grounds from the tip of the cone have linear relation to the effective stress which is obtained by subtracting the given pore pressure from the overburden pressure. Slopes of the straight lines when giving pore water pressure to the saturated ground and when giving pore air pressure to the saturated and the dried ground differ from each other. Also the slope depends on the angle of the shearing resistance of the ground.

贯入试验是一种地基强度试验.土的强度取决于有效应力.强度试验必须在两种不同的有效应力下进行。然后，考虑了从锥尖向地下某一点施加有效应力的贯入试验。在小型水池中进行了模型试验。可以给模型地基施加任意的上覆压力。同时，利用该试验箱研究了贯入过程中产生的孔隙水压力对贯入阻力的影响。1)在粘性地基的贯入试验中，贯入速度越低，贯入阻力越大。其原因是，当渗透速率较低时，由于产生的孔隙水压力消散，圆锥尖端周围的地基强度接近排水强度。2)低孔隙比时，饱和土的静力和动力贯入阻力均大于干土，高孔隙比时，干土的静力和动力贯入阻力均大于饱和土。其原因是由于锥尖周围的粘性产生的孔隙水压力。3)从锥尖向砂土地基施加孔压时，砂土地基的静、动贯入阻力与上覆土压力减去给定孔压所得的有效应力成线性关系。在饱和土中施加孔隙水压力时，以及在饱和土和干土中施加孔隙空气压力时，直线的斜率是不同的。坡度还取决于地面抗剪角度。