Earthquake resistant reliable design on agricultural hydraulic structures.

农业水工建筑物抗震可靠设计

基本信息

批准号：
06660299
负责人：
SHIMIZU Hideyoshi
金额：
$ 1.34万
依托单位：
Gifu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06660299/
关键词：
Hydraulic structure Earthquake resistant design Wave propagtion method Observation of micro tremor Statistics of extremes Earthquake-induced acceleration 耐震設計地震危険度異方性

项目摘要

Firstly, measurements of compressive and shear wave velocities are carried out by downhole and refraction wave propagation techniques at dam site composed of Diatomaceous mudstone to estimate the distributions of in situ velocities. The compressive wave velocities obtained from both downhole and refraction methods increase linearly with depth, whereas the shear wave velocities increase in proportion to a function of the power of 1/6-1/7 of depth, which is different from the distribution of velocities measured at an embankment.Secondly, observations of micro tremor are also conducted to anticipate the eigen frequency at same site. The predominant frequency observed is 0.3Hz, so that the depth of suface deposit is estimated about 400m using above-mentioned distributions of shear wave velocities.Thirdly, to investigate the deformation characteristics in small strain region, both triaxial compression (UU) and dynamic tests are performed in cylindrical specimens of Diatomaceous mudstone prepared in vertical and horizontal directions with mechanical anisotropy. The results obtained are as follows :(1) Specimens with the higher strain level exhibit the greater anisotropy as reflected by the ratio between the horizontal to vertical Young's moduli.(2) The dynamic test results indicate that the strain dependency of Young's modulus in vertical direction exists to some degree even at 10^<-6> strain level.Finally, the seismic risk analysis is performed employing the distribution of annual maximum acceleration with an upper bound limit at above-mentioned site, obtained from a theory of extremes using seismological data. As a result, it is shown that the acceleration value expected during 100 years is 160gal, which is about the same as the present design ground acceleration, whereas the upper limit acceleration value is about 450gal ; this must be taken into account in the eartquake resistant design.

首先，通过井下和折射波传播技术在由硅藻泥岩组成的坝址进行压缩波和剪切波速度的测量，以估计原位速度的分布。井下法和折射法测得的压缩波速均随深度线性增加，而剪切波速则随深度的1/6~1/7次方成比例增加，与实测速度分布不同其次，还进行了微震观测，以预测同一地点的特征频率。观测到的主频率为0.3Hz，因此利用上述剪切波速度分布估计地表沉积深度约为400m。第三，通过三轴压缩（UU）和动力试验研究小应变区域的变形特征。在垂直和水平方向制备的具有机械各向异性的硅藻泥岩圆柱形样品中进行。得到的结果如下：（1）应变水平越高的试样表现出越大的各向异性，这通过水平与垂直杨氏模量之比反映出来。（2）动态测试结果表明，垂直方向杨氏模量的应变依赖性即使在10^<-6>应变水平下，方向也存在一定程度的差异。最后，利用上述地点的年最大加速度的上限分布进行地震风险分析，该分布是根据极值理论获得的地震数据。结果表明，100年内预计加速度值为160gal，与目前设计地面加速度大致相同，而上限加速度值约为450gal；抗震设计必须考虑到这一点。