抄録
A two-phase mixture model for predicting the stress-strain relationship of mixtures with different materials is proposed based on consideration of the stress distribution and strain energy in the mixture. Elastic moduli of mixtures with two different elastic materials are estimated by the proposed model and its validity is confirmed by comparing with the calculated results from other theories and the experimental results. In-situ cement-treated soils are regarded as a kind of two-phase mixture consisting of improved and unimproved parts, and the proposed model is applied to such in-situ treated soils. A level of mixing of the treated soils is evaluated using the improvement rate obtained from the improved area in a cross section of sampling specimen. Deformation modulus and unconfined compressive strength of the in-situ treated soil with different improvement rates are derived based on the two-phase mixture model. In order to confirm the validity of the proposed equations, laboratory model tests simulating the actual mixing process at site were conducted and the calculated results were compared with the test results. The proposed equation for estimating the in-situ strength of the treated soils was also verified by the results of the in-situ improvement tests.
