Research methods: The K30 test method is adopted to test the bed coefficient of subgrade soil and the comparisons and analyses of the test result of K30 test with standard lateral pressure penetration test, press-meter test and indoor test are made.
Research conclusions: The stability K30 test is better, so it is suitable to use K30 test method to test the bed coefficient of subgrade soil. However, when there is no condition to do K30 test, it is suggested to adopt standard lateral pressure penetration test, pressure-meter test and indoor test. The tests results should be modified with the standards and experience because the bed coefficient of subgrade soil obtained from indoor test is smaller than that from K30 test.
2007, Vol. 24 
