十字板强度推算的抗剪强度指标在箱简型基础设计计算中的应用

新型箱筒型防波堤基础稳定性计算与抗剪强度指标的取值密切相关。在天津港地区,上覆较厚的软粘土层,处于欠固结状态,含水率高,承载力低。在施工期稳定性分析中,目前以十字板强度在工程中应用最广泛,但十字板强度实际上是土体各滑动面的抗剪强度的小值,单一的十字板强度指标无法估算新型箱筒型基础的地基土压力及承载力等。基于十字板强度随深度线性分布的规律及摩尔-库伦抗剪强度原理,结合收集的大量十字板强度实测数据,通过回归统计分析推算出地基土的2个抗剪强度指标,可应用于新型箱筒型基础稳定性和承载力的计算。该方法具有一般性,还可用于软粘土土坡稳定分析。

Calculating the Strength Parameters from Vane Strength and Its Use in Cylindrical Caisson foundation Design

The safety factors of the new foundation type for breakwaters,the cylindrical caisson foundation,are closely concerned with the strength parameters.In Tianjin Harbor,the foundation soils are soft clay with underconsolidated condition,low bearing capacity and high water content.The vane strength is more frequently used among the currently used strength parameters in assessing the stability analysis of the structure during the construction stage.Research results have shown that the vane strength is the smaller one comparing with the strength on other shear surfaces.Furthermore,a single value of vane strength can not meet the requirements for calcula ting the earth pressure and bearing capacity.This paper presents a new approach which can deduce the two conventional strength parameters based on the linear distribution of vane strength along the depth and the Mohr-Coulomb strength mechanism,by the statistical regression methods.The deduced parameters have been used to calculate the stability of the cylindrical caisson foundation.