Assessing interaction between the components in the soil–cement composite model

Soil massifs have close contact with foundations, piles, enclosing and fixing structures (anchors, dowels, retaining walls), as well as reinforcing soil during grouting with injection veins. Many bodies are composed of hardening cement that has an interfacial boundary with the soil. The soil–material system can be considered as a composite, in which the components exhibit new qualities when interacting. Experimental studies of cement interaction with enclosing fine soil and hard rock have been performed. The interaction specifics controlled by the material, the concentration of the binder, the surface type, watering, as well as mutual penetration of cement and enclosing rocks are studied. Special methods of shear testing based on soil samples of pile models made of cement material have been developed. The results of studying the effect of smooth and rough surfaces upon waterlogging are presented; the values of friction coefficients, contact cohesion, and stickiness are given. A dependence is proposed for determining the limit shear stresses of composite models upon the contact between sands and hard rocks with the material of dies. For rocks in which the hardening of the pile material was modeled, the values of the limit stresses and shear strain modulus were obtained depending on the binder concentration in the cement mortar.