砂および粘性土の原位置における動的変形特性の簡易推定法 : 地盤の動的変形特性の評価法に関する研究(III)

Abstract

In this paper, the authors proposed the simple prediction method on the in-situ dynamic deformation properties of sands and clays for the seismic response analysis of the ground. This method is based on the Hardin-Drnevich model (hereafter referred to as the H-D model). The results of this study may be summarized as follows. (1) The simple prediction formula on the reference strain in the H-D model was proposed. This formula makes possible to predict the reference strain easily by using the normalized initial shear modulus, which is the function of the initial shear modulus, void ratio and confining pressure. (2) In order to verify validity of the simple prediction formula on the reference strain, the results predicted by the proposed formula were compared with the test results in the laboratory by the authors and other investigators. The predicted results are in fairly good agreement with the test results. (3) The authors showed the empirical curve to evaluate the maximum damping ratio in the H-D model on the basis of the fines content measured from the simple grain size analysis. (4) The results of (1), (2) and (3) in the above indicate that the three parameters; that is, the initial shear modulus, reference strain and maximum damping ratio, which specify the H-D model, can be easily evaluated by means of the data obtained by the in-situ test and conventional soil investigation. Therefore, even when it is difficult to conduct the laboratory dynamic test, this simple prediction method can be applicable for practical purposes.