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

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.