The Adaptability Of DDC Method Based On The Composite Foundation Of Weathering Granite Filling Area

This paper takes several major industrial projects which are under construction in Guangxi as the project background, and a technologically advanced, economical, safe and reliable foundation treatment method (DDC method) was introduced according to the engineering characteristics of the large granite residual fill of this study. DDC method, a new treatment technology of foundation, apply to field tests, indoor experiments and computer simulation experiment so as to study the applicability of this method in weathered granite fill district.This paper discusses the basic characteristics of weathered granite, and analyzes the reinforcement mechanism, superiority, technical features and the existing calculation theory of DDC method, demonstrate the feasibility of DDC method in the treatment of granite residual soil.A series of quantitative formulas are established to control the foundation treatment process according to the three stages of foundation treatment (foundation treatment design-advance estimate, foundation treatment and construction-in-process control, foundation treating detection-testing).Through the regression analysis, this paper amended the traditional calculation formulas of composite foundation bearing capacity, established the relationship among the correction formula of bearing capacity of composite foundation, tamping energy, tamping settlement and dynamic penetration blow count. It also put forward the regression formulas between dynamic penetration blow count and composite foundation bearing capacity, studied the dynamic consolidation stability rules of the DDC method, provided the standard of the suggestions for the composite foundation construction and the detection time of bearing capacity.Through indoor physical-mechanical properties test, coMParing and analyzing the coMPaction effect before and after the reinforcement within the length limits of pile, the physical-mechanical properties of fills were improved.Ultimately, using the ABAQUS finite element software for computer simulation. In this simulation, soil was simulated by the Mohr-Coulomb model, and the shear dilatancy properties of pile has been taken into consideration, so, the test model is more reasonable. Through computer simulations, prior to construction to obtain the relevant parameters, not only can be controlled in advance to improve design efficiency, but also can predict the results of the field test.