Report No.: CCEER-92-5

Authors: Raj Siddharthan and Zia Zafir

Date: September 1992

Sponsoring Agency: National Science Foundation

Performing Organization:

Department of Civil Engineering/258

University of Nevada, Reno

Reno, NV 89557

Summary:

The response of a soil deposit subjected to moving surface pressure loads is of interest in various areas of engineering and physics. The free field response is required in the design of blast structures. Most of the existing methods of analysis do not account for various factors such as two dimensional wave propagation, soil layering, nonlinear soil behavior and coupling of a soil-water system. However, a select few methods which account for these factors, are based on finite element or finite difference method and, thus, result in a major computational effort. This research proposes a more efficient, continuum based approach for the analysis of the layered soil deposits under moving loads.

A computer program MOVLOAD was developed which can account for different factors such as nonlinear soil properties, inertia and damping of the soil. Any number of layers and any load distribution can be used for the surface pressure. The soil layers can be treated as porous or nonporous material (i.e. saturated layers as porous and dry layers as nonporous).

The results from the parametric studies are reported in four professional papers (Zafir & Siddharthan 1992, Siddharthan et al., 1992 (a), Siddharthan et al., 1992 (b) and Siddharthan et al., 1991) as documented below. These four publications, together comprise our project report. The results of the analyses show that the response near the surface can be substantially affected by the properties of the soil and the porefluid, and therefore, a more realistic nonlinear material model is necessary in soil response studies. The response results are also substantially affected by the speed of the moving load, compressibility of the porefluid and the permeability of the soil (Summary by authors).

(1) Zafir, Z. and Siddharthan, R. "Dynamic Response of Elastic Layered Medium to Moving Loads". Proceedings, The 33^rd AIAA/ASME/ASCE/AHS/ASC Annual Conference of. Structures, Structural Dynamics & Materials, Dallas, TX, April 13-15, 1992, Vol. 3, pp. 1549-1557.

(2) Siddharthan, R., Zafir, Z. and Norris, G. M. "'Moving Load Response of Layered Soil I: Formulation". Submitted for publication in ASCE Journal of Engineering Mechanics, March 1992 (a).

(3) Siddharthan, R., Zafir, Z. and Norris, G. M. "Moving Load Response of Layered Soil II: Verification and Application". Submitted for publication in ASCE Journal of Engineering Mechanics, March 1992(b).

(4) Siddharthan, R., Anooshehpoor, A., and Epps, J. A. "Model Tests for Moving Load Effects on Pavements". Transportation Research Record No. 1307, TRB, 1991. pp. 20-28.