| In order to meet the need of the quantity of traffic increasing rapidly,it has been an important mode of basic traffic investment construction for China’s future to the widening and rebuilding of the expressway,but there are less technology standards,basic study and engineering experience about it.This article researches on the problem of differential settlement and influences each other of new and existing subgrad systematically,and analyzes it,the article,on the design,construction and settlement survey about widening and rebuilding of Shenyang’s forth expressway.The present status and engineering application of the study about extend of expressway is overall studied earnestly by me,the full absorbing domestic and overseas research findings and engineering experience,the article analyzes and summarizes common disease and genesis mechanism about montaging new and existing subgrad.For the characteristic of widening subgrad inhomogeneous deformation,the article applies initial stress field and Element Birth and Death technology to simulate process of construction.Given the consolidation theory of subgrade Biot and Drucker-Prager nonlinear constitutive model of base soil body,it establishes a finite element method of widening subgrad inhomogeneous deformation.It also analysis systematically the influence of widening subgrad inhomogeneous deformation due to widening subgrad width,widening height,ground modulus of compression,ground modulus of compression of recent ground and widening mode.The article reveals general characteristic of widening subgrad differential settlement and clear-cut the controlling ways of differential settlement of new and existing subgrade.On the basis of elastic layered theory and subgrad differential settlement as the deformation of semi-rigid road surface structure level,the planar finite element mode of semi-rigid road surface structure stress is established on the condition of subgrad differential settlement.The regularities of distribution of the emi-rigid road surface stress are analyzed on the condition of widening subgrade.The influence of road surface structure stress is analyzed on account of the subgrad differential settlement grade and road surface structure modulus.Based on the definitude of widening subgrad disease mechanism and differential settlement of new and existing subgrade,against foundation modulus,nature of recent subgrade,widening height,widening width and the contact of new and existing junction surface and other effecting the qualitative of subgrade widening engineering,the article analysis summary corresponding measure of subgrade widening engineering.Combining the practice of widening engineering domestic,the article presents synthetic measure of widening subgrad montage and identifies technological principle of various measures,applying approach,construction technology and the requirement of quality control.With the design,construction,settlement observation of the forth widening and rebuilding of Shenyang’s forth expressway,for example,this article analyzes the main application technology method of new and existing subgrade montage,and value it with the data of settlement observation,then calculate the final settlement according to the theory which used in the comparative research of monitoring data of final settlement. |
