动力触探杆长适应性及其修正试验

西部地区河床深厚覆盖层勘探取样及工程特性是水电工程地质勘察中常遇技术难题，动力触探(dynamic penetration test，DPT)因操作简单、适用土类多而成为西部地区河床覆盖层原位测试首选方法.现行规范仅给出了20 m杆长范围的修正方法，但对超此范围重型、超重型动力触探杆长适用性及修正问题，长期以来业内则颇多争议却少有研究.鉴于此，利用现场试验与数值模拟相结合，通过对动力触探试验杆上各测点应变现场实测并得到各测点应力分布，再利用LS-DYNA软件进行反演分析并确定相关计算参数，而后进行杆长25 m、40 m、60 m、80 m、120 m的数值模拟计算得到了杆长适用范围及修正系数.试验研究方法及成果可供类似问题研究与深厚覆盖层地区工程勘察借鉴或参考. 

Adaptation and Correction of Dynamic Penetration Rod Length

In the geotechnical investigation of hydropower projects in western China, exploratory sampling and engineering property research are challenging on account of the thick overburden on the riverbed. The dynamic penetration test(DPT) has become the preferred method of in-situ tests for the river overburden layers in western China due to its simple operation and applicability for different soil types. The current standard only provides a correction method for the rod length within 20 m. For the problems of adaptation and correction of heavy and extra-heavy dynamic penetration rod length, there is always much controversy but rare research for a long time. To address this issue, a study is conducted, involving the following procedures. Firstly, combined with the field test and numerical simulation, the stress value of each monitoring point is obtained by monitoring the rod of field DPT. Then, LS-DYNA software is used for inverse analysis and relevant parameters are determinined. Lastly, different rod lengths of DPT, such as 25 m, 40 m, 60 m, 80 m and 120 m, are simulated, and the adaptation and correction of rod length are obtained. The research method and results can be used for reference in similar problems and other geotechnical investigation practices in areas with deep river overburden layers.