基于原位旁压试验的切线模量法及其初步验证

切线模量法根据原位压板载荷试验求取不同荷载水平下土体的切线模量,并将其应用于分层总和法进行地基沉降计算,较好地克服了通常取样扰动的不利影响,并能够反映地基沉降的非线性,是目前地基沉降计算中较实用有效的方法之一。而其不足之处则是原位压板试验工作量大、时间长,且难以反映深部土体的特性;相比而言,旁压试验设备轻便、测试时间短,且可在不同深度的土层进行测试,可以算是一种简单实用的原位试验。因此,为了进一步发展和完善切线模量法,本文探讨了利用原位旁压试验获取切线模量法计算参数的方法,并通过位于美国Texas AM University河滨校区的粉细砂地基上4个不同压板尺寸载荷试验结果,检验了其可行性。结果表明:4个不同压板尺寸载荷试验的沉降计算结果与试验结果具有较好的一致性,初步验证了基于原位旁压试验的切线模量法的可行性。

Tangent modulus method based on in-situ pressuremeter tests and its preliminary validation

The tangent modulus method is a method which is based on the plate loading tests to obtain the tangent modulus of the soil under different load levels, and uses the tangent modulus into the layer-wise summation method for calculating foundation settlement. It is one of the best methods for settlement calculations at present, which can overcome the adverse effects of sampling disturbance and reflect the nonlinearity of foundation settlement. However, the deficiency of the tangent modulus method based on the plate loading tests is that the plate loading tests need a heavy workload and cannot reflect the characteristics of soil in deep layers. While, compared with the plate loading tests, the pressuremeter tests take the advantages of simple operation and can test the soil with different depths, which can be said as simple and practical in-situ tests. Therefore, in order to further develop the tangent modulus method, one method in which the pressuremeter tests are used to obtain the parameters of the tangent modulus method is studied, and its feasibility is verified by the results of four plate loading tests with different sizes, which are tested in one fines sand foundation of Texas A&M University riverside campus. The results show that the calculated results of settlement curve of four plate loading tests with different sizes agree with the experimental ones, which preliminarily verifies the feasibility of the tangent modulus method based on the in-situ pressuremeter tests.