基于U型钢板桩施工的动态勘察技术的现场试验研究

FIELD EXPERIMENTAL STUDY ON DYNAMIC INVESTIGATION TECHNIQUE BASED ON THE CONSTRUCTION OF U-SHAPED STEEL SHEET PILE

针对灾害边(滑)坡的应急加固处置,提出了"动态勘察"的概念。基于"动态勘察"的目标,选择U型钢板桩作为灾害边(滑)坡的应急加固支挡结构。结合U型钢板桩的三种压入工法,分别采集了其压桩曲线图谱,对其进行了量化分析,定义了一系列的量化参数,分析了压桩曲线图谱与地层强度间的内在联系,分别拟合3种压入工法的压桩数据与地层强度特征值之间的经验关系式,并进行了工程实例的验证。试验结果表明,压桩曲线在地层分界面处会发生变化,可用于判断分界面位置;压桩曲线在不同地层会呈现不同特征,可利用经验公式近似预测地层强度。因此,利用压桩曲线特征与地层强度间的对应关系来进行"动态勘察"是可行的。

The concept of dynamic prospecting is presented aiming at emergency slope reinforcement. Based on the target of dynamic prospecting,the steel sheet pile is chosen to be used to emergency slope reinforcement. Combined with three pressing methods of U-shaped steel sheet pile,the pressing curves of each construction method are collected. And the pressing curves are on the quantification analysis. A series of quantitative parameters are defined. The internal relationship between the pressing curves and the strength of layers is analyzed. The empirical formulae for the piling data of three construction methods and strength characteristic value of layers are fitted or derived,which are verified by project examples. The results show that pile pressing curves present different changes in the interface of layers,which can be used to judge the location of interfaces. Pile pressing curves in different layers present different characteristics,and the empirical formulae can be used to predict the strength of layers. Therefore,it is feasible for'dynamic investigation'to utilize the corresponding relationships between the characteristics of the pile pressing curves and strength of layers.