Concrete Core Cement Soil Mixing Pile Mechanism Of Settlement Of Composite Foundation Loads

Concrete-cored DCM (Deep Cement Mixing) pile is a new material pile which is formed by inserting precast reinforced concrete core promptly into the cement-soil mixing pile. At present, the investigation on the bearing capacity mechanism of this pile has been mature, but the research on the settlement calculation of the Concrete-cored DCM pile and the working mechanism of the composite foundation bearing capacity is relatively insufficient. Based on a great deal of achievements on pile foundation, this paper presents a deep analysis and discussion on the single Concrete-cored DCM pile settlement and the working mechanism of the Concrete-cored DCM pile composite foundation by applying the pile-soil interaction theory and the finite element simulation analysis method. Main achievements are concluded as follows:1. To establish a mechanics model which adapts to the pile-soil interaction on the Concrete-core DCM pile, to put forward the analytic methods of transfer analysis on Concrete-cored DCM pile as well. According to the pre-established differential equation, the iterative analytical method is established. Furthermore, the loads-settlement curve of Concrete-cored DCM pile is obtained by means of iterative analytical method.2. To calculate the settlement of single Concrete-cored DCM pile by applying the improved Shear-Deformation method, elastic theory method and the loads-transferring method respectively. Combined with the engineering examples, comparisons on engineering applicability of such methods are completed.3. To analyze the load allocation of the inner core and outer core on the single Concrete-cored DCM pile top and the changing law of load transfer ratio on the inner core pile side by means of finite element simulation analysis method when the loads vary.4. To analyze the changing law of the pile top settlement when the factors influencing single Concrete-cored DCM pile settlement change, to put forward valuable suggestions on the designing parameters as well. Comparison is made on the changing characteristics of pile side friction and pile top settlement of cement-soil mixing pile, concrete pile and Concrete-cored DCM pile when the loads vary, with the final conclusion is deduced that the bearing capacity of Concrete-cored DCM pile is maximal while the settlement is minimal.5. To analyze the Load-Transferring Mechanism of the Concrete-core DCM pile composite foundation. Especially the changing law of the P-S curves of composite foundation, the stress distribution at the pile top, vertical stress of the inner core and outer core, side friction of pile when the loads, the area and length of the core pile, cushion thickness and compression modulus vary.