考虑侧向变形的软土地基非线性沉降计算的简化法

发布时间：2018-06-29 19:14

本文选题：软土沉降 + 侧向变形　；参考：《岩土工程学报》2017年09期

【摘要】：软土地基侧向变形占总沉降的比例大,通常的计算方法采用有侧限的一维压缩状态下的压缩模量应用于分层总和法来计算,这样的方法不能反应侧向变形对总沉降的影响,而规范方法则在该方法计算结果的基础上乘以1.1~1.7的经验系数,以修正计算误差。但经验系数的选取具有较大的人为性。为此,在广义胡克定律的基础上推导出可考虑侧向变形的计算方法,把软土地基沉降分为有侧限的压缩沉降S_c和侧向变形产生的沉降S_d两部分,前者采用传统的e p曲线分层总和法计算,后者采用基于e p曲线和邓肯张(Duncan Chang)本构模型的概念求取非线性割线模量E_p应用于分层总和法计算,这样就可以由e p曲线进行考虑软土侧向变形的非线性沉降计算。另外,鉴于工程中初始孔隙比e_0和压缩模量Es1-2(压力为100 kPa和200 kPa对应的压缩模量)是常用的参数,相对稳定且可较好反映软土的特性,建立了由e_0和E_(s1-2)求e p曲线和e lgp曲线的方法,从而可以求出不同应力水平下的压缩模量Esi,由Esi进行S_c和S_d的计算,实现可由初始孔隙比e_0和压缩模量E_(s1-2)进行考虑软土侧向变形的非线性沉降计算,为工程计算带来极大的方便。最后通过案例说明方法的可行性。
[Abstract]:The lateral deformation of soft soil foundation accounts for a large proportion of the total settlement. The compression modulus in the one-dimensional compression state with lateral limit is usually used to calculate the total settlement by the method of stratified summation. This method cannot reflect the effect of lateral deformation on the total settlement. On the basis of the results of the method, the gauge method is multiplied by the empirical coefficient of 1.1 to 1.7 in order to correct the calculation error. But the selection of empirical coefficient is more artificial. Therefore, based on the generalized Hook's law, the calculation method of lateral deformation is deduced, and the settlement of soft soil is divided into two parts: the compression settlement SC with lateral limit and the settlement sd caused by lateral deformation. The former is calculated by the traditional stratified summation method of e p curves, and the latter is calculated by using the concept of e p curve and Duncan Chang constitutive model to calculate the nonlinear Secant modulus ESP and apply it to the calculation of the stratified summation method. In this way, the nonlinear settlement of soft soil considering lateral deformation can be calculated by e p curve. In addition, since the initial void ratio E _ S _ 0 and compression modulus es _ 1-2 (compression modulus corresponding to pressure of 100 KPA and 200 KPA) are commonly used in engineering, they are relatively stable and can better reflect the characteristics of soft soil. In this paper, the method of finding e _ p curve and e _ (s1-2) curve from E _ S _ 0 and E _ (s1-2) is established, so that the compression modulus (E _ I) of different stress levels can be obtained, and the calculation of SC and S _ d can be carried out by ESI. The nonlinear settlement calculation considering lateral deformation of soft soil can be carried out by the initial void ratio E _ 0 and compression modulus E _ (s1-2), which brings great convenience to engineering calculation.
【作者单位】：广东省水利水电科学研究院;华南理工大学土木与交通学院;广东省岩土工程技术研究中心;
【基金】：国家自然科学基金项目(51378131) 广东省水利科技创新项目(2009-25)
【分类号】：TU433

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