Study On The Increment Mechanism And Design Application Of Bearing Capacity In Reinforced Foundation

Reinforced foundation technology has gained more and more popularity inhighway, railway, municipal, construction and other fields for its remarkable technicaland economic benefits. Reinforced foundation can effectively improve the foundationbearing capacity and deformation coordination, and reduce settlement and unevensettlement.Because research on the mechanism of reinforced foundation and bearingcapacity enhancement principle is insufficient, theoretical research is far behind theengineering practice, lacking the support of theoretical design method the design ofreinforced technology is still in the stage of experience at present, severely restricting itsuse. The paper is a part of the development plan project Mountainous Area ofGeotechnical Engineering (IRT1045), affiliated the ministry of education Yangtze Riverscholars and innovation team. On the basis of previous research, the paper includes thetheoretical research and numerical analysis methods, the comprehensive research ofreinforced foundation soil stress and stress change rule, ribbon affected zone slip lineshape characteristic, the bearing capacity and limit analysis incremental design methodis established and provide theoretical guidance for reinforcement of foundation design,the main research work are as follows:①The model test research is mainly focused on the reinforced ribbon stress andfoundation stress of destruction of reinforced area. Through analysis of reinforced andunreinforced foundation bearing capacity and settlement deformation characteristics,foundation is mainly studied in active status area, transition area, passive status area andpassive zone anchorage stress change rule section of the ribbon, the ribbon influencezone soil stress change rule, revealing the ribbon of soil stress in the foundation.②According to the ribbon to the effect of the foundation soil, the reinforcedfoundation stress calculation model was established, analyzed the foundation within theactive state area, transition area, passive state area soil shear stress change, combinedwith the Mohr-Coulomb theory, using stress analysis method and geometry method toobtain the stress solution; The numerical simulation reveals ribbon stress and soil stresschange rule of reinforced foundation.③Through analysis of unreinforced soil slip line theory, combining with thereinforced soil mechanism, establish the slip line calculation model, according to thereinforcement of foundation district boundary conditions, obtain the ribbon slip line solution and stress solution of impact area, and reveals the ribbon in the reinforcedfoundation has formed a high stress zone.④Based on the results of reinforced foundation slip line analysis and constructsthe reinforced foundation static and mobile fields; Limit theorem is used to solve theribbon affects the energy dissipation rate, establish the virtual power equation of pureclay reinforced foundation and the general soil reinforced foundation, solve the upperlimit value of bearing capacity of reinforced foundation; establish the static fieldequation of pure clay reinforced foundation and the general soil reinforced foundation,solve the lower limit value of bearing capacity of reinforced foundation; Through theanalysis of the difference of upper limit and lower limit, and determine the limit valueof upper limit bearing capacity, and analyzes the pure clay reinforced foundation and thegeneral soil reinforced foundation limit value.⑤Based on the existing design method of reinforced foundation bearing capacity,according to the theory of limit analysis of reinforced, using upper limit and lower limitvalue to solve the ultimate bearing capacity increment of reinforced, used strength shearcoefficient and ribbon displacement coefficient, to solve the incremental design method.Taking the first-stage project of Tian Jiang Ding Cheng plot fill soil foundation as ademonstration, the Increment of foundation bearing capacity which designed by limitanalysis method and the actual bearing capacity of reinforced static load test results fitwell with numerical results, verify the reliability of limit analysis.