Integrated System of Back Analysis for Geotechnical Survey

在岩土工程中，必须准确地估计地下状态，地质勘察起着至关重要的作用。然而，众所周知，地面材料不可避免地是不均匀的，并且经常是非线性的。传统的现场试验，如平板加载试验、钻孔压力试验、卢昂试验等，所获得的材料性能通常是基于解析解确定的，不能考虑材料的不均匀、层理的无序或边界形状的不规则等因素。从这个意义上讲，对材料性质进行反分析具有重要意义，但该反问题往往是不适定的，因此很难建立一种通用的、准确的方法。Ichikawa发展了一种基于对偶边界控制概念的足够通用的方法，并将其应用于线弹性问题(Ichikawa和Ohkami 1992)和粘弹性问题(Ohkami和Ichikawa 1996)。这种理论概念必须应用于实际工程问题，因此我们开发了一个三维有限元程序，它提供了一个设计良好的输入输出界面。参与这个国际项目的成员如下：Y.Ichikawa，T.G.Seki，X.Wu(日本名古屋大学)；G.Swoboda(奥地利因斯布鲁克大学)；Gioda，A.Cividini(意大利米兰诺技术大学)。

In geotechnical engineering, we must estimate the underground state precisely, thus the geological surveying plays an essential role. However, as well-known, the ground materials are inevitably inhomogeneous, and are frequently of nonlinearity. The material properties obtained by conventional in situ tests such as the plate loading test, bore hole pressure test, Lugeon test have been determined on the basis of analytical solutions usually, which cannot take the inhomogeniety of materials, disorder of layrs or irregular shape of boundary, et al.into account. In this sense, the inverse analysis for identifying material properties is of important meaning.Unfortunately the inverse problem is usually ill-posed, so it is difficult to establish a general and accurate method. Ichikawa developed a sufficiently general method based on a dual boundary control concept, and it is applied to the linear elastic problem (Ichikawa and Ohkami 1992), and the viscoelastic problem (Ohkami and Ichikawa 1996).This kind of theoretical concept must be applied to practical engineering problems, so we have developed a three dimensional finite element code which provides a well-designed input-output interface.The members involved in this international project are as follows : Y.Ichikawa, T.Seki, X.Wu (Nagoya University, Japan) ; G.Swoboda (Innsbruck University, Austria) ; G.Gioda, A.Cividini (Technical Univresity of Milano, Italy).