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针对湿陷性黄土地区公路建设中的地基承载力问题,以兰州南绕城某立交上更新统湿陷性黄土为研究对象,开展了浸水前、后土体浅层平板载荷试验与静力触探测试,结合土体物理指标变化,分析了浸水前后黄土地基承载力的损失规律。研究结果表明,原状黄土地基破坏形式为典型的整体剪切破坏,地基承载力特征值可达165k Pa,与陇西地区新黄土地基承载力经验回归关系式较吻合;浸水后由于土体软化,破坏形式更趋近于局部剪切破坏,承载力特征值约为85k Pa。静力触探测试成果表明,浸水后黄土地基的承载力损失百分比与含水率均随深度增加而减小,地表处承载力损失最大,达58%,6m以内损失率约为20%~50%,6~10m深度范围内损失率随深度增加由50%降为25%。
Aiming at the problem of the bearing capacity of foundation in highway construction of collapsible loess area, taking the Pleistocene collapsible loess on an interchange of Lanzhou city around the city as the research object, the shallow plate load test and the static contact In combination with the change of physical indexes of soil, the law of loss of bearing capacity of loess foundation before and after soaking was analyzed. The results show that the failure mode of intact loess foundation is a typical whole shear failure, the characteristic value of foundation bearing capacity is up to 165k Pa, which is in good agreement with the empirical regression equation of bearing capacity of new loess foundation in Longxi area. After soaking, the soil softens and destroys The form closer to the local shear failure, the bearing capacity characteristics of about 85k Pa. Static penetration test results show that the percentage of bearing capacity loss and moisture content of loess foundation decrease with the increase of depth after flooding, the loss of bearing capacity at surface is the largest, reaching 58%, and the loss rate of 6m is about 20% -50% , The loss rate in the depth range of 6 ~ 10m decreased from 50% to 25% with the increase of depth.