静力触探估算安徽省淮北平原黏性土物理力学指标方法研究

Determination of physical and mechanical properties indexes of cohesive soil in Huaibei Plain of Anhui Province by CPT

文章将地区经验与静力触探(cone penetration test,CPT)方法相结合,估算土层物理力学指标,通过收集整理安徽省淮北平原200余份工程勘察资料,统计计算淮北平原地区黏性土比贯入阻力p_(s)值的算术平均值、厚度加权平均值和最小平均值,分析p_(s)值3种统计平均值和各常用物理力学性质指标的统计学特征和相关性,并逐一进行回归拟合分析和检验。结果表明:p_(s)值3种统计平均值的统计学特征无显著差异,而各物理力学性质指标的统计学特征各异,导致p_(s)值统计平均值与各指标之间的相关性和拟合回归效果差异明显;除液限、塑限和塑性指数等少量指标外,p_(s)值的3种统计平均值与各常用物理力学性质指标具有高度相关性,回归拟合效果良好;p_(s)值最小平均值与各主要物理力学性质指标的相关性最高,回归拟合效果最优。经检验并与相关规范对比,建议淮北平原黏性土可采用p_(s)值最小平均值按文中建立的回归方程确定主要物理力学性质指标,并给出采用p_(s)值最小平均值划分黏性土稠度状态的方案。

The physical and mechanical properties indexes of soil layers are estimated by integrating the local experience with the cone penetration test(CPT)method.The arithmetic average,thickness weighted average and minimum average of specific penetration resistance(p_(s))of cohesive soil layers are statistically calculated based on more than 200 geotechnial engineering investigation data from Huaibei Plain,Anhui Province.Then,the statistical characteristics and correlation of these three statistical averages and common physical and mechanical properties indexes are analyzed,and the regression fitting analysis and tests are carried out one by one.The results show that there is no significant difference in the statistical characteristics of these three statistical average values,but the statistical characteristics of each physical and mechanical property index are different,resulting in significant differences in the correlation and regression fitting effect between these three statistical average values and each physical and mechanical property index.Except for a few indexes such as liquid limit,plastic limit and plasticity index,these three statistical average values have high correlation with those commonly used physical and mechanical properties indexes,and the regression fitting effect is good.And especially,the correlation between the minimum average value of p_(s) and the main physical and mechanical properties indexes is the highest,and the regression fitting effect is the best.After testing and comparing with other codes,it is suggested that the minimum average value of p_(s) can be used to determine the main physical and mechanical properties indexes of cohesive soil layers in Huaibei Plain according to the regression equations established in this study,and a scheme for dividing the consistency state of cohesive soil by the minimum average value of p_(s) is proposed.