發(fā)布時間：2018-09-19 12:31

【摘要】：本論文依托于國家自然科學(xué)基金項目:“格柵蠕變時砂卵石填料長期工作機(jī)理研究”,對加筋土結(jié)構(gòu)的力學(xué)性狀進(jìn)行了研究。加筋土結(jié)構(gòu)在港口碼頭、道路工程、地下工程、邊坡工程等中的應(yīng)用的廣泛性,近年來,發(fā)現(xiàn)加筋土結(jié)構(gòu)在長期荷載作用下加筋體中的筋材產(chǎn)生的蠕變松弛對加筋土的強(qiáng)度和穩(wěn)定性有影響,所以有必要對加筋土結(jié)構(gòu)的力學(xué)性狀進(jìn)行研究。本文的研究主要有以下幾個方面:第一方面,利用剪力滯后理論的計算方法對加筋土結(jié)構(gòu)進(jìn)行受力分析,力學(xué)建模,研究得到各層筋材的應(yīng)變和位移。計算結(jié)果表明各層筋材的應(yīng)變值都是沿著筋材長度方向波動,各層筋材上應(yīng)變最大值并不是發(fā)生在筋材與擋墻接觸處,各層筋材的應(yīng)變最大值發(fā)生在接觸處和筋材一半之間的某個位置。第二方面,通過室內(nèi)的拉拔試驗,首先得到了筋材的應(yīng)變并結(jié)合流變體的粘彈性蠕變模型研究了筋材在考慮應(yīng)力水平下的蠕變情況。其次由于土體各向異性的存在,而現(xiàn)在的加筋土數(shù)值模擬大多數(shù)沒有考慮到土體的各向異性,所以利用多次回填多次測試取應(yīng)力應(yīng)變均值的辦法來考慮土體各向異性對筋材應(yīng)力應(yīng)變的影響。第三方面,本文在考慮筋材與填料在似摩擦作用下,得到了加筋土的主動區(qū)的計算方法,與規(guī)范采用的0.3H的方法進(jìn)行對比。分析了主動區(qū)跟似摩擦系數(shù)、擋墻墻高、筋材間距等因素對主動區(qū)的影響,研究表明加筋間距對主動區(qū)的擴(kuò)展影響最大。第四方面,首先利用水平層分析法解析了加筋土墻背土壓力,得到了加筋土墻背土壓力與墻高的函數(shù)關(guān)系,并與文獻(xiàn)的實測資料進(jìn)行了對比驗證。其次分析了填料的內(nèi)摩擦角,擋墻墻高,摩擦系數(shù)等因素對加筋土墻背土壓力的影響。再利用試驗得到的土工格柵的本構(gòu)關(guān)系,建立加筋土中各層筋材的應(yīng)變預(yù)測方法,用此預(yù)測方法可以估計加筋土中筋材的壽命。最后分析了筋土之間的似摩擦系數(shù)、擋墻墻高等因素對應(yīng)變預(yù)測的影響。
[Abstract]:Based on the project of National Natural Science Foundation of China: "Study on long-term working mechanism of sand-gravel filling during grid creep", this paper studies the mechanical properties of reinforced soil structure. It is necessary to study the mechanical properties of reinforced soil structures because creep relaxation of reinforcement materials in reinforced bodies under load has an effect on the strength and stability of reinforced soil. The results show that the maximum strain of each layer is not at the contact point between the reinforcement and the retaining wall, and the maximum strain of each layer occurs somewhere between the contact point and the half of the reinforcement. In this paper, the strain of reinforcement is obtained by pull-out test in laboratory, and the creep behavior of reinforcement under stress level is studied by viscoelastic creep model of rheological body. The influence of soil anisotropy on the stress and strain of reinforcement material is considered by means of the mean value of stress and strain measured many times. Thirdly, the calculation method of active zone of reinforced soil is obtained by considering the effect of similar friction between reinforcement material and filler, and is compared with the 0.3H method adopted in the code. The research shows that the reinforcement spacing has the greatest influence on the expansion of the active zone. Fourthly, the horizontal layer analysis method is used to analyze the earth pressure behind the reinforced earth wall, and the functional relationship between the earth pressure behind the reinforced earth wall and the wall height is obtained. The influence of the internal friction angle of the filler, the height of the retaining wall and the friction coefficient on the back earth pressure of the reinforced earth wall is analyzed. Then the strain prediction method of the reinforcement in each layer of the reinforced earth is established by using the constitutive relation of the geogrid obtained from the test. The life of the reinforcement in the reinforced earth can be estimated by this prediction method. Friction coefficient and retaining wall high factor correspond to the influence of variable prediction.
【學(xué)位授予單位】：重慶交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU43

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本文編號：2250126