Research Initiation: Insitu Pore Water Pressure PredictionsDuring Earthquakes

当含水饱和的松散砂受到剧烈地震震动引起的循环荷载时，如果水不易排出（不排水行为），则会产生超孔隙水压力。这种超孔隙压力降低了土的强度，如果产生足够的压力，将导致土的破坏称为液化。目前预测循环加载过程中孔隙水压力产生的方法往往对产生的压力预测过高，即预测保守。本研究项目旨在研究目前用于预测地震产生的孔隙水压力的土壤模型的准确性，并特别关注地震期间和地震后孔隙水压力消散的影响。正在将这些预测与实验室测试数据以及利用日本东京湾大尾岛一个仪器站点进行的实地测试获得的数据进行比较。这些数据包括松散砂质底土中两个深度的地面运动时程和动态孔隙水压力测量。

When loose sands saturated with water are subjected to the cyclic loads resulting from severe earthquake shaking, excess pore water pressures are generated if the water cannot easily drain away (undrained behavior). This excess pore pressure reduces the soil strength, and if sufficient pressure is generated, will lead to a failure of the soil referred to as liquefaction. Current methods for predicting the generation of pore water pressure during cyclic loading often overpredict the pressures generated, that is, they result in conservative predictions. This research project is investigating the accuracy of soil models currently used for the prediction of earthquake-generated pore water pressures, with special attention being given to the effect of the dissipation of this pressure during and after the earthquake. The predictions are being compared with laboratory test data as well as data obtained from field tests using an instrumented site at Owi Island, Tokyo Bay, Japan. This data includes ground motion time histories as well as dynamic pore water pressure measurements at two depths in the loose sandy subsoils.