新型固化劑改良黃土邊坡穩(wěn)定性分析
發(fā)布時間：2018-10-09 11:40
【摘要】：黃土特有的高壓縮性、濕陷性、強度低等不良工程特性，使得其必須經(jīng)處理后方能滿足高速公路、鐵路路基和水利壩基等設(shè)計、施工及使用要求。工程上常見的處理方式有換填、打樁、加入固化材料等，方式多種多樣，效果也各不相同。新型固化劑由于其優(yōu)良的物理力學(xué)性能正在被廣泛的研究并試用于基礎(chǔ)工程中。 本文采用新型高分子材料SH固化劑改良黃土，在參閱文獻和室內(nèi)試驗的基礎(chǔ)上，就改良黃土邊坡的穩(wěn)定性進行數(shù)值模擬分析研究。 主要工作及取得的成果如下： （1）進行固化劑SH改良黃土相關(guān)試驗和結(jié)果分析。由SH摻量和含水率對改良黃土抗剪強度的影響曲線知，固化劑SH能明顯提高黃土抗剪強度，且對改良黃土黏聚力的影響要大于內(nèi)摩擦角。含水率對改良黃土的抗剪強度影響顯著等結(jié)論。試驗數(shù)據(jù)為改良黃土邊坡穩(wěn)定性數(shù)值模型參數(shù)選取提供了較科學(xué)的事實依據(jù)。 （2）建立BP神經(jīng)網(wǎng)絡(luò)預(yù)測模型。選取室內(nèi)土工試驗數(shù)據(jù)作為學(xué)習(xí)樣本和測試樣本，就含水率對改良黃土力學(xué)參數(shù)的影響進行了預(yù)測分析，，預(yù)測結(jié)果與試驗結(jié)果基本吻合�？梢妼P神經(jīng)網(wǎng)絡(luò)用于抗剪強度參數(shù)預(yù)測是可行的，從而實現(xiàn)了由物理指標(biāo)到力學(xué)參數(shù)轉(zhuǎn)化，為改良黃土性能探究提供了一種新的研究方法。 （3）將強度折減法應(yīng)用到大型通用有限元軟件ABAQUS中，分析探討了改良黃土的邊坡穩(wěn)定性，模擬了彈性模量、泊松比、加固厚度、坡角、土體重度及含水率等物理力學(xué)參數(shù)對邊坡穩(wěn)定性的影響。在邊坡變形分析中，論證了固化劑SH加入黃土邊坡表層的可行性，研究發(fā)現(xiàn)，含水率和土體重度對改良黃土邊坡的水平位移、隆起位移及下滑位移影響較大，邊坡角度、泊松比與彈性模量的影響較��；通過敏感性分析得出了固化劑SH的最優(yōu)加固厚度及影響因素，模擬結(jié)果顯示，含水率對改良黃土邊坡安全系數(shù)的敏感度最大，其次是土體重度，彈性模量和泊松比對安全系數(shù)的敏感度較小，與邊坡變形分析結(jié)論基本一致。因此在施工或者運行期間應(yīng)格外重視水位變化等對邊坡穩(wěn)定性的影響，做好相關(guān)預(yù)防和治理工作。 通過上述研究分析,得出固化劑SH應(yīng)用到黃土邊坡改良領(lǐng)域是科學(xué)合理的，研究結(jié)果對黃土邊坡改良技術(shù)及黃土地區(qū)地質(zhì)災(zāi)害的防治提供了理論參考價值。
[Abstract]:Because of its high compressibility, collapsibility and low strength, loess must be treated before it can meet the design, construction and application requirements of expressway, railway subgrade and water conservancy dam foundation. The common treatment methods in engineering are filling, piling, adding solidified materials and so on. Because of its excellent physical and mechanical properties, the new curing agent is widely studied and used in foundation engineering. In this paper, a new polymer material, SH curing agent, is used to improve loess. On the basis of literature and laboratory tests, the stability of improved loess slope is studied by numerical simulation. The main work and results obtained are as follows: (1) relevant experiments and results analysis of SH curing agent for loess improvement are carried out. According to the influence curve of SH content and moisture content on the shear strength of improved loess, the curing agent SH can obviously improve the shear strength of loess, and the influence on the cohesion of improved loess is greater than that of internal friction angle. The effect of moisture content on the shear strength of improved loess is significant. The experimental data provide a scientific basis for the selection of the parameters of the numerical model for improving the stability of loess slope. (2) the prediction model of BP neural network is established. The influence of moisture content on the mechanical parameters of improved loess is predicted and analyzed by using the data of indoor geotechnical test as the learning and testing samples. The predicted results are in good agreement with the experimental results. It can be seen that it is feasible to apply BP neural network to predict the shear strength parameters, thus the conversion from physical index to mechanical parameter is realized, which provides a new research method for improving loess performance. (3) the strength reduction method is applied to the large scale finite element software ABAQUS. The stability of the improved loess slope is analyzed and discussed. The elastic modulus, Poisson's ratio, reinforcement thickness and slope angle are simulated. The influence of physical and mechanical parameters such as soil weight and moisture content on slope stability. In the analysis of slope deformation, the feasibility of adding SH to the surface layer of loess slope is demonstrated. It is found that the moisture content and the soil weight have great influence on the horizontal displacement, uplift displacement and glide displacement of the improved loess slope, and the slope angle. The influence of Poisson's ratio and elastic modulus is small, through sensitivity analysis, the optimum reinforcement thickness and influencing factors of curing agent SH are obtained. The simulation results show that the sensitivity of moisture content to the safety factor of improved loess slope is the greatest, followed by the serious soil mass. The sensitivity of elastic modulus and Poisson ratio is relatively small, which is consistent with the conclusion of slope deformation analysis. Therefore, during construction or operation, we should pay special attention to the influence of water level change on slope stability, and do a good job of prevention and treatment. Through the above research and analysis, it is concluded that the application of SH to loess slope improvement is scientific and reasonable, and the research results provide theoretical reference value for loess slope improvement technology and the prevention of geological disasters in loess area.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU444;TU43
本文編號：2259207
[Abstract]:Because of its high compressibility, collapsibility and low strength, loess must be treated before it can meet the design, construction and application requirements of expressway, railway subgrade and water conservancy dam foundation. The common treatment methods in engineering are filling, piling, adding solidified materials and so on. Because of its excellent physical and mechanical properties, the new curing agent is widely studied and used in foundation engineering. In this paper, a new polymer material, SH curing agent, is used to improve loess. On the basis of literature and laboratory tests, the stability of improved loess slope is studied by numerical simulation. The main work and results obtained are as follows: (1) relevant experiments and results analysis of SH curing agent for loess improvement are carried out. According to the influence curve of SH content and moisture content on the shear strength of improved loess, the curing agent SH can obviously improve the shear strength of loess, and the influence on the cohesion of improved loess is greater than that of internal friction angle. The effect of moisture content on the shear strength of improved loess is significant. The experimental data provide a scientific basis for the selection of the parameters of the numerical model for improving the stability of loess slope. (2) the prediction model of BP neural network is established. The influence of moisture content on the mechanical parameters of improved loess is predicted and analyzed by using the data of indoor geotechnical test as the learning and testing samples. The predicted results are in good agreement with the experimental results. It can be seen that it is feasible to apply BP neural network to predict the shear strength parameters, thus the conversion from physical index to mechanical parameter is realized, which provides a new research method for improving loess performance. (3) the strength reduction method is applied to the large scale finite element software ABAQUS. The stability of the improved loess slope is analyzed and discussed. The elastic modulus, Poisson's ratio, reinforcement thickness and slope angle are simulated. The influence of physical and mechanical parameters such as soil weight and moisture content on slope stability. In the analysis of slope deformation, the feasibility of adding SH to the surface layer of loess slope is demonstrated. It is found that the moisture content and the soil weight have great influence on the horizontal displacement, uplift displacement and glide displacement of the improved loess slope, and the slope angle. The influence of Poisson's ratio and elastic modulus is small, through sensitivity analysis, the optimum reinforcement thickness and influencing factors of curing agent SH are obtained. The simulation results show that the sensitivity of moisture content to the safety factor of improved loess slope is the greatest, followed by the serious soil mass. The sensitivity of elastic modulus and Poisson ratio is relatively small, which is consistent with the conclusion of slope deformation analysis. Therefore, during construction or operation, we should pay special attention to the influence of water level change on slope stability, and do a good job of prevention and treatment. Through the above research and analysis, it is concluded that the application of SH to loess slope improvement is scientific and reasonable, and the research results provide theoretical reference value for loess slope improvement technology and the prevention of geological disasters in loess area.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU444;TU43
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