下辽河平原区剪切波速与土层埋深关系分析

Analysis of relationship between shear wave velocity and depth of soil layers in downstream Liaohe River plain

土体剪切波速是岩土工程勘察和地震安全性评价应用最广的参量之一。依据下辽河平原区大量的钻孔实测剪切波速数据,探讨了不同土类剪切波速与埋深间的关系:通过最小二乘法分别采用线性模型、指数模型和一元二次多项式模型建立了按土性分类的土体剪切波速与埋深间的统计公式,以拟合优度为评价指标进行对比选择,并与《构筑物抗震设计规范》的经验公式及工程场地实测结果进行了对比。结果表明:所推荐的剪切波速与埋深间的统计公式优于规范的经验公式;采用推荐公式与实测结果进行了土层地震反应分析对比,结果表明,两者计算结果差别不大,均可用于下辽河平原区一般建筑的工程勘察与地震安全评价。

The shear wave velocity of soils is one of the most widely used parameters in the field of seismic safety evaluation of engineering sites and geotechnical investigation. Based on analysis of the shear wave velocity data of lots of boreholes from downstream Liaohe River plain, we discussed the relationship between different shear wave ve- locity and depth of soils. The regression equations of shear wave velocity and depth of different soils, considering all kinds of soils and least squares method, were established by using three statistical models of the linear equation, ex- ponent equation and quadratic polynomial with one variable, respectively. The goodness of fitting was taken as an evaluation index to acquire the recommended models and parameters between shear wave velocity and depth of dif- ferent soils. The equations recommended were compared with the formula in the Chinese design code for earthquake resistance of special structures（ GBS0191 -93 ） and with the measurements from sites. The results indicate that the equations of relationship between the shear wave velocity and the depth of different soils recommended by this arti- cle get the better of the empirical equations in the Chinese design code for earthquake resistance of special struc- tures（GBS0191 -93）. By discussing the equations recommended and results of site measurement, the seismic re- sponse analysis of layered soil sites is processed respectively. Calculation result shows that the difference between both condition is non-significant by and large. It could therefore be argued that both of the results can be applied to the seismic safety evaluation of engineering sites and geotechnical investigation in downstream Liaohe River plain.