【摘要】：地鐵長期運(yùn)行的重要影響之一是地層沉降、差異沉降及其所致的次生問題。未來幾年,西部黃土地區(qū)將展開一定規(guī)模的城市軌道建設(shè),以西安地鐵為例,其大部分正線段均在地下水位以下,屬于力學(xué)性能較差的飽和黃土。地鐵荷載對地層累積變形的影響更不能小覷。目前,鮮見綜合考慮飽和黃土結(jié)構(gòu)性、各向異性、地鐵循環(huán)荷載特性的動力本構(gòu)模型,本文將綜合考慮這三種因素的影響,建立一種新的土動力本構(gòu)模型,并將其應(yīng)用于地鐵隧道周圍地層的沉降特性分析,取得了如下研究成果： (1)將土的結(jié)構(gòu)性因子劃分為各向同性結(jié)構(gòu)性因子Di和各向異性結(jié)構(gòu)性因子Dr,假定各向異性結(jié)構(gòu)性損傷對邊界面的各向異性張量和臨界狀態(tài)線斜率均有影響,建立了考慮各向異性結(jié)構(gòu)性影響的旋轉(zhuǎn)硬化法則。同時,沿用了前人所建立的考慮各向同性結(jié)構(gòu)性損傷影響的等向硬化法則。 (2)綜合考慮循環(huán)加卸載影響及前兩種硬化法則,建立了映射中心的運(yùn)動硬化法則,假定在加載方向改變時,映射中心會移至應(yīng)力反向點(diǎn)處,且隨著邊界面的前兩種硬化過程而發(fā)生運(yùn)動硬化。 基于Dafalias邊界面模型及上述三種硬化法則,建立了綜合考慮各向異性、結(jié)構(gòu)性和循環(huán)動荷載作用的飽和黃土動力邊界面本構(gòu)模型。對模型參數(shù)進(jìn)行了分類,并詳細(xì)描述了各參數(shù)的物理意義及確定方法。 (3)將本文邊界面模型編寫成UMAT子程序,利用ABAQUS有限元軟件模擬了飽和黃土試樣的室內(nèi)動、靜三軸試驗(yàn)過程,利用數(shù)值模擬結(jié)果與室內(nèi)試驗(yàn)結(jié)果的一致性驗(yàn)證了本文本構(gòu)模型及UMAT子程序的合理性。 (4)基于此UMAT子程序及建立的間歇性循環(huán)動荷載模型,考慮孔壓消散與土層沉降的耦合效應(yīng),建立了地鐵荷載-隧道-飽和黃土地層的二維有限元模型,分析了飽和黃土地層在地鐵運(yùn)行過程中的長期沉降規(guī)律和影響因素,并預(yù)測了長期沉降的影響范圍、沉降大小及趨于穩(wěn)定的時間。
[Abstract]:Ground subsidence, differential settlement and secondary problems are one of the important effects of long-term operation of subway. In the next few years, urban track construction will be carried out on a certain scale in the loess region of western China. Taking Xi'an Metro as an example, most of the positive sections are below the groundwater level, which belongs to saturated loess with poor mechanical properties. The influence of subway load on the accumulated deformation of the ground can not be underestimated. At present, there are few dynamic constitutive models considering the structural characteristics of saturated loess, anisotropy and cyclic load characteristics of subway. In this paper, a new soil dynamic constitutive model is established considering the influence of these three factors. And it is applied to the analysis of the settlement characteristics of the subways around the tunnel. The results are as follows: (1) the structural factors of soils are divided into isotropic structural factors (Di) and anisotropic structural factors (Dr,). The anisotropic structural damage is assumed to be anisotropic Zhang Liang on the boundary surface. And critical state line slope. A rotation hardening rule considering anisotropic structural effects is established. At the same time, the law of isotropic hardening considering the influence of isotropic structural damage is adopted. (2) considering the cyclic loading and unloading effect and the first two hardening laws, the motion hardening law of the mapping center is established. It is assumed that when the loading direction changes, the mapping center will move to the reverse point of the stress, and the motion hardening will occur with the first two hardening processes of the boundary surface. Based on the Dafalias boundary surface model and the above three hardening rules, a dynamic boundary surface constitutive model of saturated loess considering anisotropic, structural and cyclic dynamic loads is established. The model parameters are classified, and the physical meaning and determination method of each parameter are described in detail. (3) the boundary surface model of this paper is compiled into UMAT subroutine, and the indoor motion of saturated loess specimen is simulated by ABAQUS finite element software. In the static triaxial test process, the rationality of the text construction model and the UMAT subroutine is verified by the consistency between the numerical simulation results and the indoor test results. (4) based on the UMAT subroutine and the intermittent cyclic dynamic load model established, Considering the coupling effect of pore pressure dissipation and soil layer settlement, a two-dimensional finite element model of underground load-tunnel saturated loess layer is established, and the long-term settlement law and influencing factors of saturated loess layer in the course of subway operation are analyzed. The influence range, the settlement size and the time of stabilization of the long-term settlement are predicted.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TU444;TU43

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 閆維明;張yN;任珉;馮軍和;聶晗;陳建秋;;地鐵運(yùn)營誘發(fā)振動實(shí)測及傳播規(guī)律[J];北京工業(yè)大學(xué)學(xué)報;2006年02期

2 吳義祥;工程粘性土微觀結(jié)構(gòu)的定量評價[J];中國地質(zhì)科學(xué)院院報;1991年02期

3 韓日美;;西安地鐵黃土隧道工程特性分析及對策[J];都市快軌交通;2010年06期

4 王蘭民;西部大開發(fā)中的黃土地震災(zāi)害問題[J];地學(xué)前緣;2001年01期

5 林杜軍;西安市近期飽和黃土的工程地質(zhì)特征[J];地質(zhì)災(zāi)害與環(huán)境保護(hù);1994年01期

6 周尚國;;黃土隧道的主要地質(zhì)災(zāi)害類型[J];地質(zhì)與勘探;2007年02期

7 王志強(qiáng);;甘肅引洮供水工程飽和黃土工程地質(zhì)研究[J];工程地質(zhì)學(xué)報;2005年04期

8 王國欣;肖樹芳;;土結(jié)構(gòu)性本構(gòu)模型研究現(xiàn)狀綜述[J];工程地質(zhì)學(xué)報;2006年05期

9 胡偉;韓建剛;;結(jié)構(gòu)性飽和黃土動力特性試驗(yàn)研究[J];工程地質(zhì)學(xué)報;2009年05期

10 傅世法;;論飽和黃土[J];工程勘察;1982年01期

相關(guān)博士學(xué)位論文 前1條

1 袁俊;城市軌道交通隔振減振機(jī)理及措施研究[D];西安建筑科技大學(xué);2010年

，

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