Development of In-situ Test for Estimating Deformation and Strength Parameters from Shock Loading

开发用于估计冲击载荷变形和强度参数的现场测试

基本信息

批准号：
12650490
负责人：
ARAI Katsuhiko
金额：
$ 0.9万
依托单位：
Fukui University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650490/
关键词：
ShockLoad WeightDrop Test In-situtest Deformation Modulus Strength Parameters Back Analysis

项目摘要

This study tries to estimate the deformation and strength parameters of ground from the results of shock loading test using drop of weight. The stress-strain relationship employed in the analysis, is the linear elasticity before yielding, and the associated flow rule based on Mohr-Coulomb yield criterion after yielding. By using Newmark β method, we can get the time history of shock acceleration, velocity and displacement. Secondly we performed a lot of weight drop tests using Toyoura sand and weathered sand. The estimated displacement which is calculated by integrating the monitored acceleration, gives almost the same value as the one observed by high speed video camera and the final.displacement observed by lazar sensor. The parametric study based on numerical analysis shows that the shock velocity is little affected by the material parameters, and that the displacement is useful for back analysis of material parameters. Since the final displacement is affected both by deformation modulus and friction angle φ, it is difficult to back calculate the deformation modulus and friction angle separately. Since the confining pressure is small near ground surface, the deformation modulus becomes considerably small on the ground surface. Considering these properties, the deformation modulus is estimated by the static loading test separately performed. By using the deformation modulus, the results of shock loading test is fairly well simulated by the numerical analysis. Based on this method, it is possible to back calculate the friction angle from the shock loading test. When the soil deposit has two strength components of cohesion and friction angle, there is the possibility that we can back analyze these two strength components separately by repeating the shock loading test with changing the drop height.

本研究尝试根据落锤冲击载荷试验的结果来估计地面的变形和强度参数。分析中采用的应力-应变关系是屈服前的线弹性，以及基于莫尔的相关流动法则。屈服后的库仑屈服准则通过使用Newmark β方法，我们可以得到冲击加速度、速度和位移的时间历程，然后我们使用Toyoura砂和风化砂进行了大量的跌落试验，通过积分计算出估计的位移。监测到的加速度，基于数值分析的参数研究表明，冲击速度受材料参数的影响很小，并且位移是有用的。由于最终位移受变形模量和摩擦角 φ 的影响，因此很难分别反算变形模量和摩擦角，因为靠近地表的围压较小，变形模量也较大。考虑到这些特性，变形模量是通过单独进行的静载试验来估算的，通过使用变形模量，可以通过数值分析很好地模拟冲击载荷试验的结果。，可以通过冲击载荷试验反算摩擦角当土体具有粘聚力和摩擦角两个强度分量时，我们有可能通过重复冲击载荷试验分别反推这两个强度分量。改变跌落高度。