紫色土抗剪强度差异分析及土坎优化设计

选择钙质紫色土和中性紫色土为工程试样,通过室内多级三轴剪切试验测定了含水率和干密度交互作用对土坎稳定性重要指标——土壤抗剪强度指标的影响,确定了紫色土土坎坎高及外边坡稳定角的取值,以优化土坎设计.结果表明:干密度和含水率交互作用对土壤粘聚力的影响下,钙质紫色土和中性紫色土土坎土质的最优含水率分别为11%,8%,最优干密度分别为1.7,1.68g/cm3;在紫色土最优干密度和含水率下,考虑占地和稳定性因素,钙质紫色土土坎高度不宜超过2.0m,其外边坡坡度角可设计为80°;中性紫色土土坎高度不宜超过1.5m,其外边坡坡度角可设计为60°.本文旨在为紫色土区国土整治土坎修筑工程提供理论指导.

Optimum Engineering Design of Purple Soil Ridges Based on an Analysis of Purple Soil Shearing Strength

In order to provide a theoretical guidance for building soil ridges in land consolidation in purple soil areas ,a multiple triaxial shearing test in lab was conducted with calcareous purple soil and neutral purple soil as the experiment materials to study the effects of soil water content and soil dry density on soil shearing strength ,which is the key indicator of ridge stability .The heights and outside slope angles of the two kinds of purple soil were determined so as to optimize soil ridge designing .Under the influence of the interaction between soil dry density and soil water content on soil cohesion ,the optimal soil water content of calcareous purple soil and neutral purple soil was estimated to be 11% and 8% and the optimal soil dry density was 1.7 g/cm3 and 1.68 g/cm3 ,respectively .Taking into consideration the covering area and ridge stability ,the height of the calcareous purple soil ridge and the neutral purple soil ridge should not exceed 2.0 m and 1.5 m ,and their outside slope angles should be 80°and 60° ,respectively ,under the optimal soil water content and soil dry density .