确定地基承载力的p-s曲线法  

Determining foundation bearing capacity of p-s curve method

作　　者：杨光华[1] YANG Guang-hua(Guangdong Research Institute of Water Resources and Hydropower/The Geotechnical Engineering Technology Center of Guangdong Province,Guangzhou 510610,Guangdong,China)

机构地区：[1]广东省水利水电科学研究院/广东省岩土工程技术研究中心,广东广州510610

出　　处：《地基处理》2022年第2期91-98,共8页Journal of Ground Improvement

基　　金：国家自然科学基金项目(52078143)。

摘　　要：地基承载力是土力学的基本问题,也是土力学创立近百年还没有解决好的一个难题。目前认为确定地基承载力最可靠的方法是压板载荷试验,但压板载荷试验存在尺寸效应,其确定的地基承载力一般只保证地基的强度要求,并不能保证实际基础的变形要求。最好的方法是用实际基础的荷载沉降p-s曲线来确定地基的承载力,由实际基础的p-s曲线可以同时获得满足强度和变形双控要求的地基承载力,这就必须要解决实际基础的p-s曲线的计算问题。压板载荷试验是最接近基础实际受力状态的试验,探索通过压板载荷试验的p-s曲线去计算实际基础的荷载沉降p-s曲线的方法是解决的途径。文中分析了直接用压板试验确定地基承载力的不足和困难,通过假设压板试验的p-s曲线符合双曲线,则可由压板试验的p-s曲线确定土层的初始切线模量E0和地基的强度指标黏聚力c和内摩擦角φ,在已知土层的变形和强度指标参数E0、c、φ后,即可用切线模量法计算实际基础的荷载沉降p-s曲线,为破解地基承载力确定的难题提供了有效的方法。Foundation bearing capacity is not only a basic problem of soil mechanics, but also a difficult problem that has not been solved in the past hundred years. At present, it is considered that the most reliable method to determine the bearing capacity of foundation is plate load test. However, size effect exists in plate load test. The bearing capacity of foundation determined by plate load test can only meet the strength requirement of foundation, but not the deformation requirement of actual foundation. The best method is to determine the bearing capacity of the foundation by using the p-s curve of load settlement of real foundation. Based on the p-s curve of the actual foundation, the bearing capacity of the foundation can be obtained simultaneously to meet the requirements of both strength and deformation control. Therefore, the calculation problem of p-s curve of the actual foundation must be solved. The stress state in plate load test is the closest to the real stress state of the foundation. So it provides a good solution to explore the method of calculating the load settlement p-s curve of the actual foundation through the p-s curve of plate load test. In this paper, the deficiencies and difficulties of determining bearing capacity of foundation by plate load test are analyzed. Assuming that the p-s curve of the plate load test is hyperbolic, the initial tangent modulus E0, cohesion c and internal friction angle φ of the soil layer can be determined from the p-s curve of the plate load test. After the deformation and strength index parameters E0, c and φ of the soil layer are known, the tangent modulus method can be used to calculate the p-s curve of load settlement of the actual foundation,which provides an effective method to solve the problem of determining the bearing capacity of foundation.

关 键 词：地基承载力 压板载荷试验 荷载沉降p-s曲线 切线模量法 尺寸效应 

分 类 号：TU470[建筑科学—结构工程]