地基承载力机理及新计算方法

地基承载力计算是土力学中的基本课题,但地基土自重对承载力的贡献一直未能较准确地予以计算,究其原因在于此部分的计算不是孤立的.为深入探讨地基承载力的机理及计算理论,首先,证明基础埋深相应超载及地基土重度对承载力的作用可分别转换为等效黏聚力及黏聚力随深度的增长率.随后,针对承受非偏心竖向荷载的条形基础下地基的整体剪切破坏,...

Mechanism and new calculation method for bearing capacity of foundations

The calculation of bearing capacity of foundations is a fundamental topic in soil mechanics.However,the contribution of the unit weight of the foundation soil to the bearing capacity cannot yet be satisfactorily calculated.The fundamental reason is that this part of bearing capacity is actually not independent,and consequently cannot be calculated separately.In order to study the mechanism of foundation bearing capacity and the relevant theory thoroughly,it is first revealed that the surcharge load corresponding to footing embedment and the unit weight of the foundation soil,multiplied by the soil strength parameter tanφ,can be treated respectively as the equivalent cohesion and the rate of cohesion increase along depth.Then a new method is developed for the general failure mode of strip footing under non-eccentric vertical loads.In this new method a non-dimensional parameter is defined to well reflect the influences of the soil strength and soil weight on the bearing capacity,and based on which a unified formula for the calculation of bearing capacity is established,in which the soil strength,the embedment depth of the footing and the soil weight are all considered as closely related elements.For the bearing capacity of foundation under other more complicated conditions,such as failure in local mode,different footing shapes,inclined loads etc.,the available methods of treatment can be still applied in combination with the newly developed formula.Careful comparison with the refined numerical calculations proves the reliability and high accuracy of the proposed formula,and at the same time it proves the rationality and correctness of the whole idea as well as the constructed non-dimensional parameter.Besides,comparisons are also made with the formulas by Terzaghi and Hansen to show the significant improvement of the proposed method over the formers.