| Over the past 30 years,the calculation and analysis of pile foundation has made significant progress.Under the effect of international technology of pile foundation and engineering application,the study of pile foundation in our country developed very rapidly.Owing to its high bearing capacity,small settlement and applicable to various complicated geological conditions,pile foundation are widely used in various kind of foundation engineering such as industrial and civil buildings,road and bridge engineering,water resources and hydropower engineering,airport and station,harbour and offshore production etc.At present, domestic and foreign researches on the theory of pile is relatively mature.For the characteristic of Pile foundation-Soil-pile foundation(PSP) interactive system are complexity and practicability,it is more significance and application value in research of PSP interactive system.In the process of research for PSP dynamic interaction,mainly based on the dynamic interaction coefficient as to study for analysing lateral dynamic impedance of pile-groups.This paper proposes a simplified finite element method that can applied to PSP dynamic interactive system.First step was to establish the different PSP dynamic interactive system model with the simplified finite element method.Then Using the APDL language program for different simplified finite element model, drew a simplified finite element model in frequency domain dynamic response characteristics of loads.This dynamic response characteristics will compared with analysis results that through a simplified method calculate model built by Gazetas-Dobry,so as to verified the accuracy and applicability of the simplified finite element method and for the dynamic interaction analysis of PSP method provided a new theory.The main research content was as follows:(1)At first, the derivation and purport of the discussion and the studying actuality and developing level about soil-structure interaction were presented. With the summarization of lots of interrelated references, the limitations,advantages and disadvantages existing in present researches were discussed too.(2)Introduced several kinds of simplified methods and deducted their calculate formula such as lateral dynamic impedance of single pile,dynamic interactive factors of pile-groups and lateral dynamic impedance of pile-groups.(3)In view of the common PSP interactive system dynamic finite element modelthat with a huge number of nodes,large scale of calculation and low computational efficiency.This paper through the simplified calculation formula that deducted above and used the finite element ANSYS structural analysis software to write APDL language program,built 2-piles,4-piles and 9-piles simplified finite element method models.Beam element to simulate the piles and the spring damper simulate the soil at these models.(4)In order to determine the established the simplified finite element models of the vibration characteristics,obtained the models' frequency response and the shape curve,we proceeded the modal analysis and then drew a simplified finite element model(2-piles,4-piles and 9-piles) in frequency domain dynamic response characteristics of loads to got its corresponding lateral dynamic impedance of pile-groups.This dynamic response characteristics would compared with analysis results that through a simplified method calculate model built by Gazetas-Dobry,so as to verified the accuracy and applicability of the simplified finite element method.(5)Changed the simplified finite element model of the pile spacing, pile diameter and the properties of soil to simulate the PSP dynamic interaction system,and calculate dynamic interactive factors of pile-groups and lateral dynamic impedance of pile-groups. The computed results compared with the corresponding results obtained by simplified method,provides the calculation basis for the simplified finite element method that can solve the problem of PSP interaction implementation,and to simplify the finite element method to solve the theoretical basis for practical engineering application analysis problems.(6)Using the simplified finite element method to establish more close to the engineering practice of complex pile-groups models,by changing the pile spacing,pile diameter and the properties of soil to simulate different pile spacing, pile diameter and soil dynamic interaction of group piles, the influence of simulation calculation of pile foundation in soft soil, neutral soil and hard soil environment under the condition of dynamic corresponding results.To verify the feasibility of the simplified finite element method is applied to the engineering practice and practical. |
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