Loading Sequence Effects on Dragload and Downdrag for Pile Foundation

Negative skin friction (NSF) is one of the important problems when designing a pile foundation. However, the influence of loading sequence on the dragload and downdrag for pile foundation is seldom studied. In this paper, a three-dimensional numerical model was established using FLAC3D. Compared with the results of model test, the established model could be used to study the NSF of pile foundation. The influencing factors were discussed including the length-diameter ratio of pile and the loading sequence of pile head load and surcharge. A case history was analyzed using FLAC3D. The calculated results are in good agreement with the measured results. It is concluded that the dragload and downdrag are remarkably influenced by the loading sequence of pile head load and surcharge. The dragload and downdrag reach the maximum values under the condition of surcharge after pile head load.

对湿陷性黄土场地地震作用工程影响的几点看法

针对《建筑抗震设计规范》(GB50011-2001)中涉及黄土的规定,提出了看法和改进意见,就地震作用对工程的不利影响(如震陷、液化、基桩负摩擦力等),进行了分析并提出相应的工程建议;特别强调地震作用对工程影响必须考虑湿陷性黄土的含水状态。

某采空区内公路桥优化设计

采空区易引起地表沉降、塌陷等危害。为使处于采空区内的公路桥达到结构先进、安全可靠、适用耐久、经济合理的目标,设计通过采用简支结构体系,合理划分桩周土层,考虑剩余下沉位移产生负摩阻力等不利影响,合理增加基桩的安全储备;并通过增设伸缩缝、使用可调支座等构造措施,保证了桥梁结构的安全合理,满足了工程需要。

某高速公路匝道沉降事故处理分析

通过对填土引起的桥台附近地面沉降的计算，分析了某高速公路匝道处桩基础发生较大沉降的原因，介绍了一套切实可行的分析处理方法，可作为类似工程事故处理的参考。