Abstract
Before construction of any structures on surface or subsurface of alluvial clay layer, the cement mixing method is used frequently to construct a thin improved layer at certain depth of ground. However, the confirmation of improved layer is performed by only boring and laboratory testing. In the present paper, the confirmation method using s-wave reflection method, and the simulation analysis which as certain continuity of an improved thin layer is proposed. Especially in this analysis, the proposed method for the model at a thin layer of high velocity which lies between two layers of low velocity is examined, and the results of this simulation analysis are found to be applicable construction site.
