本文選題：路基拓寬 + 差異沉降��； 參考：《長安大學(xué)》2015年碩士論文

【摘要】：高速公路拓寬工程中最大的難題是解決新老路基差異沉降過大的問題,過大的差異沉降會(huì)使路面結(jié)構(gòu)產(chǎn)生附加應(yīng)力而開裂破壞,從而影響安全及使用性能。軟土地基高速公路拓寬工程,沉降主要來自于地基,此時(shí)必須采取合理有效的處治方案以控制差異沉降,實(shí)踐證明樁土復(fù)合地基可以有效地緩解這個(gè)問題。但是由于拓寬路基是一個(gè)新老路基和地基相互作用的復(fù)雜系統(tǒng),樁土復(fù)合地基在拓寬荷載作用下的控沉效果和沉降計(jì)算等還不明確,其設(shè)計(jì)也無規(guī)范可依,主要依靠經(jīng)驗(yàn)技術(shù)。滯洪區(qū)由于其歷史成因及作用,區(qū)內(nèi)表層土不能滿足拓寬工程對土質(zhì)的要求,為此本文依托滯洪區(qū)內(nèi)軟土地基高速公路拓寬實(shí)際工程,以沉降計(jì)算為目標(biāo),以不同復(fù)合地基處治方案為主線,使用有限元方法,對滯洪區(qū)道路拓寬軟基處理方案進(jìn)行了設(shè)計(jì)驗(yàn)算、評價(jià)和優(yōu)化,并基于現(xiàn)場觀測數(shù)據(jù),通過雙曲線擬合法預(yù)測最終沉降量,主要內(nèi)容如下:(1)根據(jù)工程地質(zhì)資料,分析老王坡滯洪區(qū)土體的物理力學(xué)性質(zhì),以及新老路基下地基土體性質(zhì)差異,為數(shù)值計(jì)算提供依據(jù)。(2)分析了針對道路拓寬時(shí)的有限元中二維模型與三維的適用條件,討論了利用傳統(tǒng)二維模型在樁土復(fù)合地基中建模的不足,利用有限元軟件建立拓寬路基三維模型,介紹了針對依托工程現(xiàn)場實(shí)際情況的三維建模過程。(3)采用有限元方法對老王坡滯洪區(qū)內(nèi)的地基處理擬采用設(shè)計(jì)方案進(jìn)行變形分析,得到設(shè)計(jì)方案的數(shù)值模擬結(jié)果,根據(jù)差異沉降計(jì)算結(jié)果對地基處理方案合理性進(jìn)行評價(jià)和優(yōu)化。(4)針對滯洪內(nèi)采用處理的方案,分別分析樁長、樁徑、樁間距、樁體強(qiáng)度、褥墊層模量等因素的改變對拓寬路基差異沉降的影響。(5)選取滯洪區(qū)典型斷面,進(jìn)行路基變形觀測,根據(jù)觀測結(jié)果采用沉降預(yù)測中常用的曲線擬合法預(yù)測觀測點(diǎn)的最終沉降,驗(yàn)證水泥粉煤灰碎石樁的控沉效果。
[Abstract]:The biggest problem in expressway widening project is to solve the problem of excessive differential settlement of new and old subgrade. Excessive differential settlement will cause additional stress and crack damage to pavement structure, thus affecting safety and performance. The settlement of soft soil foundation expressway widening project mainly comes from the foundation. At this time, reasonable and effective treatment scheme must be adopted to control the differential settlement. The practice has proved that pile-soil composite foundation can effectively alleviate this problem. However, widening roadbed is a complex system of interaction between new and old subgrade and foundation, so the settlement control effect and settlement calculation of pile-soil composite foundation under widening load are not clear, and its design is not standardized, but mainly depends on experience technology. Because of its historical cause and function, the surface soil in the flood detention area can not meet the requirements of soil quality of the widening project. In this paper, based on the actual project of widening the expressway with soft soil foundation in the flood detention area, the settlement calculation is the goal. Taking different treatment schemes of composite foundation as the main line and using finite element method, the design checking calculation, evaluation and optimization of the treatment scheme for widening soft foundation in flood detention area are carried out. Based on the field observation data, the final settlement is predicted by hyperbolic fitting method. The main contents are as follows: (1) based on the engineering geological data, the physical and mechanical properties of soil in Laowangpo flood detention area and the difference of soil properties under new and old subgrade are analyzed. The application conditions of 2D model and 3D model in road widening are analyzed, and the shortcomings of traditional 2D model in pile-soil composite foundation are discussed. The 3D model of widening roadbed is established by using finite element software. The process of 3D modeling based on the actual situation of engineering is introduced. The finite element method is adopted to analyze the deformation of foundation treatment in Laowangpo flood detention area. The numerical simulation results of the design scheme are obtained. According to the results of differential settlement calculation, the rationality of the foundation treatment scheme is evaluated and optimized. The influence of factors such as cushion modulus on widening differential settlement of roadbed. (5) selecting typical section of flood detention area and observing subgrade deformation. According to the observation results, the curve fitting method commonly used in settlement prediction is used to predict the final settlement of observation point. The sedimentation control effect of cement fly ash gravel pile was verified.
【學(xué)位授予單位】：長安大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U416.1

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本文編號：1889708