潍坊中南部平原地区粉土强度特性试验研究

Research on Silt Intensity in the Plain Area of South-central Weifang

以潍坊中南部地区可作为高层基础持力层的粉土作为研究对象,通过室内试验,获得粉土颗粒级配曲线、粉土试样的基本物理力学特性指标,以及不同含水率和压实度条件下粉土试样的轴向变形与偏应力。对试验结果分析发现,粉土试样颗粒级配较好,能够达到较高的压实度;根据小于最优含水率时不同含水率条件下的屈服应力,确定了粉土层应变硬化与软化的临界点位置,认为含水率、压实度及围压是影响抗剪强度的主要因素;最终获得了小于最优含水率时区域性粉土剪切极限状态线拟合方程,并发现极限状态线的斜率M(s)及其在偏应力轴上的截距μ(s)均为与含水率无关的常数。

The silt in the plain area of south-central Weifang can be used as the bearing stratum of the foundation for high-rise buildings .Laboratory experiments were conducted to obtain the grading curve of silt ,physical properties of silt ,and the axial de-formation and deviatoric stress of silt under different moisture contents and degrees of compaction .The test results showed that the silt has a good grading to reach a relatively high degree of compaction .According to the yield stress under different water contents which were less than the optimal water content ,the critical point of strain hardening and softening was determined . Water content ,degree of compaction ,and confining pressure were the main influence factors of the shear strength .The fitting e-quation of shear limit state for the regional silt was obtained when the water content was less than the optimal water content , and M（s）（slope） and μ（s）（intercept） were all constants which were independent of water content .