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.

这项研究试图通过使用重量下降的减震器测试结果估算地面的变形和强度参数。在分析中进行了应力 - 应变关系是在屈服前的线性弹性，而相关的流量规则基于屈服后基于Mohr-Coulomb屈服标准。通过使用Newmarkβ方法，我们可以获取冲击加速度，速度和位移的时间历史。其次，我们使用Toyoura的沙子和风化的沙子进行了大量的体重下降测试。通过集成监视加速度来计算的估计位移几乎具有与高速摄像机观察到的值相同的值，而最终的位置为Lazar Sensor观察到的放置位置。基于数值分析的参数研究表明，冲击速度几乎不受材料参数的影响，并且位移可用于对材料参数的背部分析。由于最终位移受变形模量和摩擦角φ都受到影响，因此很难分别计算变形模量和摩擦角。由于限制压力很小，近地面近地面，因此变形模量在地面上小心地变小。考虑到这些属性，通过分别进行静态加载测试来估计变形模量。通过使用变形模量，通过数值分析可以很好地模拟冲击载荷测试的结果。基于此方法，可以从冲击加载测试中返回计算摩擦角。当土壤沉积物具有两个内聚和摩擦角的强度成分时，我们可以通过重复减震载荷测试来分别分析这两个强度成分，并改变下降高度。