本文關(guān)鍵詞：長期循環(huán)荷載作用下飽和軟黏土靜動力特性試驗研究　出處：《江西理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 軟黏土 應(yīng)變特性 應(yīng)力-應(yīng)變滯回圈 排水條件 分階段加載

【摘要】：我國東部沿海分布著大量的軟弱土,隨著經(jīng)濟的飛速發(fā)展,有很多的大型交通設(shè)施興建在軟弱土地基上。而興建在軟弱土地基上的交通設(shè)施除承受了靜荷載外還承受著反復(fù)的循環(huán)動荷載,由于其對軟土的動力特性影響研究還不夠深入具體。因此有必要對軟黏土進(jìn)行不同周數(shù)循環(huán)荷載下的靜動力特性進(jìn)行研究。本文所采用GDS動三軸儀對土的靜動力特性進(jìn)行試驗。目的在于研究原狀土和重塑土在不同圍壓下靜力剪切時的應(yīng)變、孔壓以及應(yīng)力路徑等因素的發(fā)展規(guī)律;循環(huán)荷載土體的動力特性的發(fā)展規(guī)律以及分別在排水和不排水條件下以及連續(xù)循環(huán)荷載下和分階段循環(huán)荷載下土體的動力特性的發(fā)展規(guī)律。1通過對原狀土和重塑土在不同圍壓下的靜力剪切實驗研究得到:(1)原狀土和重塑土的應(yīng)變和孔壓在剪切過程中都經(jīng)歷過土體的彈性階段,急劇剪切階段,和破壞階段這3個類似的發(fā)展階段;在實驗過程中,重塑土的應(yīng)力-應(yīng)變曲線和有效路徑比原狀土的應(yīng)力-應(yīng)變曲線和有效路徑表現(xiàn)的更明顯。(2)同圍壓下,原狀土的應(yīng)力-應(yīng)變曲線滯后于重塑土的應(yīng)力-應(yīng)變曲線;在1%ε時,原狀土和重塑土的應(yīng)力-應(yīng)變曲線近似呈直線增長;在1%ε時,原狀土也能給-應(yīng)變曲線滯后于重塑土應(yīng)力-應(yīng)變曲線。2開展原狀土在不同循環(huán)荷載和不同排水條件的土的動力特性試驗,研究發(fā)現(xiàn):(1)土體在排水條件下的殘余應(yīng)變比不排水條件下土體的殘余應(yīng)變更大,而土體在不同排水條件下土體的累積應(yīng)變在振動前期近似呈直線增長,在振動后期排水條件下的累積應(yīng)變比不排水條件下的累積應(yīng)變增長較快;(2)在排水條件下,土體振動產(chǎn)生的應(yīng)力-應(yīng)變滯回曲線更密集,土體在排水條件下振動之后更容易首先達(dá)到穩(wěn)定狀態(tài)。3針對交通溫州軟土的動力特性設(shè)施在不同階段下土體的受荷不同,研究發(fā)現(xiàn):(1)不管是在排水和不排水條件下,土體在振動的第一階段的應(yīng)變和孔壓,累積應(yīng)變都增長較大,在隨后的振動階段內(nèi),都會有不同程度的變化;(2)在振動過程中,不排水條件下產(chǎn)生的回彈應(yīng)變一直比排水條件下振動產(chǎn)生的回彈應(yīng)變大,在第一階段內(nèi),排水條件下回彈應(yīng)變有略微減小,不排水條件下回彈應(yīng)變有略微增長;
[Abstract]:There are a lot of soft soil in the east coast of China, with the rapid development of economy. There are many large transportation facilities built on the soft soil foundation, and the traffic facilities built on the soft soil foundation bear not only static load but also repeated cyclic dynamic load. It is necessary to study the static and dynamic characteristics of soft clay under cyclic loads of different cycles. The GDS dynamic triaxial instrument used in this paper is used to study the static behavior of soft clay. The purpose of this study is to study the strain of undisturbed soil and remolded soil under different confining pressures under static shear. The development law of pore pressure and stress path; The development law of the dynamic characteristics of the soil under cyclic loading and the development of the dynamic characteristics of the soil under drainage and undrained conditions, as well as under the continuous cyclic load and the staged cyclic load. The static shear experiments of plastic soil under different confining pressures show that:. (. 1) the strain and pore pressure of undisturbed soil and remolded soil have experienced elastic stage in shear process. The rapid shear stage and the failure stage are three similar stages of development; During the experiment, the stress-strain curve and effective path of the remolded soil are more obvious than the stress-strain curve and the effective path of the undisturbed soil under the same confining pressure. The stress-strain curve of undisturbed soil lags behind that of remolded soil. At 1% 蔚, the stress-strain curves of the undisturbed soil and the remolded soil are approximately linear. At 1% 蔚, the stress-strain curve of the undisturbed soil can also lag behind the stress-strain curve of the remolded soil. 2. The dynamic characteristics of the undisturbed soil under different cyclic loads and different drainage conditions can be tested. It is found that the residual strain of the soil under the drainage condition is larger than that of the soil under the undrained condition, and the cumulative strain of the soil under the different drainage conditions increases approximately in a straight line in the early stage of vibration. The cumulative strain increases faster in the later stage of vibration than in the undrained condition. 2) under the condition of drainage, the stress-strain hysteretic curve produced by soil vibration is denser. It is easier for the soil to reach stable state at first after vibration under the drainage condition. 3. According to the dynamic characteristic facilities of Wenzhou soft soil in different stages, the soil is subjected to different loads. It is found that the strain, pore pressure and cumulative strain of soil in the first stage of vibration increase greatly, and there will be some changes in the later stage of vibration, regardless of whether the strain and pore pressure of soil in the first stage of vibration increase greatly under the condition of drainage or undrainage. 2) in the process of vibration, the springback strain under undrained condition is always larger than that produced by vibration under drainage condition, and in the first stage, the springback strain under drainage condition decreases slightly. The springback strain increases slightly under undrained condition.
【學(xué)位授予單位】：江西理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TU41

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