本文關(guān)鍵詞： 非飽和膨脹土 降雨作用 滑坡 裂隙 錨桿框架梁系統(tǒng)　出處：《西南交通大學(xué)》2014年博士論文　論文類(lèi)型：學(xué)位論文

【摘要】：膨脹土作為一種特殊性質(zhì)的土體,具有隨著含水量不斷變化表現(xiàn)出顯著的吸水膨脹、失水收縮、浸水后承載力較大幅度衰減的特征。這些有別于其它類(lèi)別土體的工程地質(zhì)特性,使得其所組成的路塹邊坡也呈現(xiàn)出特定的穩(wěn)定性能。論文以十天高速陜西漢中勉縣境內(nèi)的武侯服務(wù)區(qū)附近膨脹土路塹邊坡為研究對(duì)象,采用室內(nèi)試驗(yàn)、理論分析、計(jì)算程序開(kāi)發(fā)以及數(shù)值模擬等綜合手段,較為深入的掌握了該地區(qū)膨脹土的基本特性,進(jìn)而開(kāi)展了考慮裂隙影響的降雨誘發(fā)膨脹土滑坡變形機(jī)理、預(yù)警性降雨閾值以及膨脹土滑坡防護(hù)措施的研究工作,取得了以下幾個(gè)方面的研究成果和主要認(rèn)識(shí)：(1)通過(guò)瞬態(tài)水力特性循環(huán)試驗(yàn),得到了不同水力路徑條件下漢中地區(qū)膨脹土的土-水特征函數(shù)曲線(SWCC),并基于該曲線數(shù)據(jù)推導(dǎo)得到了相應(yīng)的滲透系數(shù)特征函數(shù)曲線(HCF)。試驗(yàn)結(jié)果表明,處于不同水力路徑進(jìn)程中的同一類(lèi)型膨脹土,會(huì)呈現(xiàn)出差異明顯的水力學(xué)特性,也即具有明顯的“滯后效應(yīng)”。從微觀結(jié)構(gòu)入手,探究了孔隙水賦存及滲流形式,揭示了非飽和膨脹土的“滯后效應(yīng)”機(jī)理。(2)基于不同水力路徑下不同含水量時(shí)的膨脹土抗剪強(qiáng)度試驗(yàn)結(jié)果表明,當(dāng)土體由飽和狀態(tài)進(jìn)入非飽和狀態(tài)后,所產(chǎn)生的基質(zhì)吸力會(huì)對(duì)土體強(qiáng)度的提升產(chǎn)生積極影響。這種強(qiáng)度貢獻(xiàn)形式,主要表現(xiàn)為通過(guò)轉(zhuǎn)化為土體粘聚力的形式來(lái)實(shí)現(xiàn)。但不能就此認(rèn)為膨脹土基質(zhì)吸力越大或含水量越低,其強(qiáng)度會(huì)相應(yīng)的持續(xù)加大。因?yàn)樵谄浜康恼Ｗ儎?dòng)范圍內(nèi),由于基質(zhì)吸力貢獻(xiàn)作用而存在一個(gè)強(qiáng)度峰值。通過(guò)對(duì)研究區(qū)飽和膨脹土樣本進(jìn)行固結(jié)試驗(yàn),掌握了該地區(qū)飽和膨脹土在不同加載條件下的固結(jié)變形特征,得到了相應(yīng)的固結(jié)變形模型方程,并將膨脹土排水固結(jié)變形情況予以程序?qū)崿F(xiàn)。按照土樣采集時(shí)所處的應(yīng)力環(huán)境進(jìn)行加載偏應(yīng)力路徑設(shè)置,完成了六級(jí)加載條件下的三軸蠕變?cè)囼?yàn)。在試驗(yàn)數(shù)據(jù)分析的基礎(chǔ)上提出了相應(yīng)的蠕變模型方程。結(jié)合固結(jié)變形與蠕變變形模型方程,對(duì)膨脹土流變特性進(jìn)行描述。(3)根據(jù)漢中地區(qū)膨脹土的XRD圖譜,確定了其產(chǎn)生脹縮特性的主要親水性礦物組份和含量,并通過(guò)微觀結(jié)構(gòu)掃描手段,確定了含水量變化時(shí),土體礦物產(chǎn)生物化反應(yīng)及土體顆粒排列與接觸形式(面-面、點(diǎn)-面以及點(diǎn)-點(diǎn)三種形式)的規(guī)律。為了進(jìn)一步分析非飽和膨脹土裂隙發(fā)育特征,基于Otsu理論的圖像分割算法編寫(xiě)了裂隙識(shí)別程序,提出了可用于描述裂隙率與含水量的經(jīng)驗(yàn)型函數(shù)關(guān)系式。(4)利用裂隙均布理論以及本文所得的裂隙率與含水量經(jīng)驗(yàn)型函數(shù)關(guān)系式,通過(guò)數(shù)值模擬手段,對(duì)不同裂隙發(fā)育狀況下的漢中地區(qū)膨脹土路塹邊坡,進(jìn)行了雨水入滲時(shí)坡體變形發(fā)展規(guī)律及潛在滑坡形態(tài)等方面的研究。較為深入的認(rèn)識(shí)了降雨誘發(fā)膨脹土滑坡的機(jī)理。在此基礎(chǔ)上,綜合考慮蒸發(fā)進(jìn)程、降雨持時(shí)以及降雨強(qiáng)度等因素的影響,提出了適用于漢中地區(qū)降雨誘發(fā)滑坡的預(yù)警性降雨閾值的經(jīng)驗(yàn)公式。(5)針對(duì)研究區(qū)雨水作用下含裂隙膨脹土路塹邊坡的工程特性,提出了錨桿框架梁式滑坡防治結(jié)構(gòu)體系,并重點(diǎn)進(jìn)行了相應(yīng)的優(yōu)化設(shè)計(jì)分析。
[Abstract]:As a kind of special soil properties of expansive soil, with water content changes showed significant swelling, shrinkage, bearing characteristics of large amplitude attenuation after immersion. These are different from other types of engineering geological characteristics of the soil, the slope of the road. Also showing a steady performance in particular. In ten days near the high-speed Shaanxi Mianxian province Hanzhoung Wuhou service area of expansive soil cutting slope as the research object, using laboratory test, theoretical analysis, numerical simulation and calculation procedures for the development of a comprehensive way, in-depth grasp of the basic characteristics of expansive soil in the area, and then carry out the deformation mechanism of expansive soil landslide induced by rainfall considering cracks the influence of rainfall warning threshold and protective measures of expansive soil landslide research work, has made the following aspects of research results and main conclusions: (1). A transient performance cycle test, the expansive soil in Hanzhoung area, different hydraulic path under the condition of soil water characteristic curve (SWCC), and based on the curve data derived permeability coefficient characteristic function of the corresponding curve (HCF). The experimental results show that in the same type of different hydraulic path in the process of expansive soil that will show obvious differences in hydraulic characteristics, which is obviously a "lag effect". Starting from the microscopic structure, explores the pore water storage and seepage, reveals the unsaturated expansive soil "lag effect" mechanism. (2) experimental results show that the strength of expansive soil based on different hydraulic path under different water content when the shear, when the soil is saturated state to unsaturated state, matrix suction generated will have a positive impact on the strength of soil improvement. The strength contribution form, mainly is through the transformation As the soil cohesion form. It can not be considered a more expansive soil matric suction or water content is low, the strength of the corresponding increase. Because in the normal range of moisture content, because the contribution of matrix suction and there is a peak intensity. By analyzing the saturated consolidation test the expansive soil samples, grasp the deformation characteristics of the area of consolidation of saturated expansive soil under different loading conditions, the model equations of deformation corresponding consolidation, and consolidation deformation of expansive soil will be program. According to the soil sampling when the stress environment loading deviatoric stress path set, completed three the triaxial creep test of six loading conditions. Based on the analysis of the test data on the creep model equations. Combining with the consolidation deformation and creep deformation model equation on the rheology properties of expansive soil Described. (3) according to the XRD of expansive soil in Hanzhoung area, the swelling characteristics of major hydrophilic mineral components and content were determined, and the micro structure of scanning method, to determine the change of water content, soil minerals to produce chemical reaction and soil particle arrangement and the contact form (face to face. Point to surface and point point) three forms of law. In order to further analyze the unsaturated expansive soil fissure characteristics, Otsu image segmentation algorithm developed fracture theory recognition program based on the proposed can be used to describe the fracture rate and type of experience type relationship moisture. (4) the use of uniform theory and fracture the fracture rate and water content of experience formula, by means of numerical simulation, expansive soil cutting slope of different crack growth under the condition of the Hanzhoung region, the rain infiltration when the slope deformation regularity and potential slip Study of slope shape. More in-depth understanding of the mechanism of rainfall induced landslide of expansive soil. On this basis, considering the evaporation process, rainfall duration, rainfall intensity and other factors influence, put forward the empirical formula of rainfall warning threshold for Hanzhoung area rainfall induced landslide value. (5) according to the project the characteristics of expansive soil slope with cracks under the effect of rain area, put forward the anchor frame beam structure of landslide prevention system, and analyzes the corresponding optimization design.

【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TU443;P642.22

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