湿陷性黄土地区公路地基承载力的评价

Evaluation of foundation bearing capacity of highway engineering in collapsible loess regions

通过西北黄土代表性区域兰州、介休、阎良等地湿陷性黄土原状地基和强夯冲击碾压处理后地基进行的室内土工试验和原位测试，对载荷试验、旁压试验、静力触探、动力触探和标准贯入等试验在公路工程地基承载力评价时的可行性进行探讨，并对强夯和冲击碾压处理黄土地基的处理效果进行分析。试验结果表明，湿陷性黄土地区公路工程地基承载力评价时，旁压试验在一定程度上可以取代浅层的载荷试验，并作为地基处理后承载力评价的主要测试方法；240t·m强夯处理湿陷性黄土地基的有效加固深度为4m，有效影响深度为5～6m；冲击碾压的有效加固深度为0.5～1.0m，有效影响深度为1～2m。

For the collapsible loess undisturbed foundations and treated foundations of representative districts of Lanzhou, Jiexiu and Yanliang, the indoor geotechnical tests and in-situ tests are carried out. The feasibilities of plate loading test, pressuremeter test, static cone penetration test, dynamical cone penetration test and standard penetration test for evaluating foundation bearing capacity of highway engineering are discussed. The treatment effects of dynamical compaction method （DCM） and impact compaction are analyzed. The test results show that the pressuremeter test can replace plate loading test of shallow loess foundation in evaluating foundation bearing capacity of highway engineering; and it could be the primary testing method for evaluating bearing capacity of treated foundation. The impacted efficiently depth of collapsible loess foundation treated by DCM （240 t·m） is 4 m; the influenced efficiently depth is 5-6 m; the impacted efficiently depth of collapsible loess foundation treated by impact compaction is 0.5-1.0 m; the influenced efficiently depth is 1-2 m.