發(fā)布時間：2018-06-07 04:27

  本文選題：淺灘區(qū) + 土工織物�。� 參考：《遼寧工程技術(shù)大學》2014年碩士論文

【摘要】：袋裝淤泥筑堤是通過充填器具直接挖取淺灘區(qū)淤泥充填到鋪設(shè)好的土工織物袋體內(nèi),達到設(shè)計強度后逐層充填最終形成堤壩。將這種工程性質(zhì)差的淤泥作為堤壩組成材料的主體,結(jié)合土工織物袋的加筋保土作用,形成具有結(jié)構(gòu)性強度的構(gòu)筑物。目前該技術(shù)還處于現(xiàn)場試驗階段,對其理論研究及袋裝淤泥堤壩變形特性分析仍很少見。本文依托蒼南縣江南海涂圍墾區(qū)吹填及軟基處理一期(A1區(qū))工程充填土袋筑堤試驗工程,結(jié)合加筋土加筋機制、土工織物袋充填特性、土體固結(jié)機理、加筋土穩(wěn)定性計算有限元法,開展了袋裝淤泥筑堤的變形特性研究,具體研究成果如下：(1)通過對袋裝淤泥強度來源分析,提出了袋裝淤泥前期強度主要由土工織物的加筋保土作用所提供,后期強度主要由固結(jié)土體的結(jié)構(gòu)性強度所提供。(2)通過對土工織物袋的受力分析,建立了描述充填袋幾何形狀的方程組,并運用Matlab軟件求得數(shù)值解。發(fā)現(xiàn)充填袋的高度與泵壓之間呈對數(shù)關(guān)系,接觸面寬度與泵壓之間呈指數(shù)關(guān)系,土工織物袋張力與泵壓之間呈線性關(guān)系。結(jié)合現(xiàn)場大尺度土工織物袋的充填形狀,建立了單層土工織物袋張力的計算公式。(3)通過算例的優(yōu)化分析,建立了試驗段的有限元模型,對比分析了Hardening-Soil模型與莫爾-庫侖模型的模擬結(jié)果,得到以下結(jié)論：堤壩寬度范圍內(nèi),基底面的垂直位移是向下的,且隨著填筑的進行,垂直位移逐漸增大；堤壩寬度范圍以外,基底面產(chǎn)生了一定量的隆起；隨著填筑的進行,基底面垂直位移隆起與壓縮的分界點逐漸遠離堤壩中軸線�；酌娴乃轿灰圃诘虊涡拗^程中呈開口向下的拋物線分布,且距堤壩中軸線9m范圍內(nèi)的水平位移增加的速度較小。隨著斷面深度的增加垂直位移逐漸減小,同一深度的垂直位移在填筑過程中也迅速增加。水平位移隨斷面深度增加先增大后減��；隨著填筑的進行,斷面同一深度各點的水平位移均有所增加。采用Hardening-Soil模型計算土體的超靜孔隙水壓力消散的較快,一年后的孔隙水壓力為2.7 KN/m2,莫爾-庫侖模型計算的結(jié)果為5.2 KN/m2,與實測值4.4KN/m2相比相差較小。隨著距堤壩中軸線距離的增加袋體軸力逐漸減小；隨著填筑的進行,基底面袋體軸力略有增加,且軸力增加的速度逐漸減小。(4)基于強度折減的有限元法計算袋裝淤泥堤壩穩(wěn)定性發(fā)現(xiàn)加筋土條分法不適用計算此類加筋土的穩(wěn)定性。
[Abstract]:The bagged silt embankment is directly excavated and filled into the geotextile bag in the shoal area by filling apparatus. After the design strength is reached, the embankment is formed layer by layer after filling. This kind of silt with poor engineering properties is used as the main body of the embankment material, and the structure with structural strength is formed by combining the reinforcement and soil preservation of geotextile bags. At present, the technology is still in the field test stage, the theoretical research and the analysis of the deformation characteristics of the bag silt dyke are still very rare. This paper relies on the filling soil bag embankment test project in Jiangnan coastal reclamation area of Cangnan county, combined with reinforcing mechanism of reinforced soil, filling characteristics of geotextile bag and consolidation mechanism of soil. The finite element method for calculating the stability of reinforced soil is used to study the deformation characteristics of the bagged silt embankment. The concrete research results are as follows: (1) through the analysis of the strength source of the bagged silt, It is proposed that the early strength of bagged silt is mainly provided by geotextile reinforcement and soil conservation, and the later strength is mainly provided by the structural strength of consolidated soil. (2) the stress of geotextile bag is analyzed by means of the stress analysis of geotextile bag. The equations describing the geometric shape of the filling bag are established, and the numerical solution is obtained by using Matlab software. It is found that there is a logarithmic relationship between the height of filling bag and pump pressure, an exponential relationship between the width of contact surface and pump pressure, and a linear relationship between the tension of geotextile bag and pump pressure. Combined with the filling shape of large-scale geotextile bags in the field, a formula for calculating the tension of single-layer geotextile bags is established. The finite element model of the test section is established through the optimization analysis of an example. The simulation results of Hardening-Soil model and Mohr Coulomb model are compared and analyzed. The following conclusions are obtained: the vertical displacement of the base surface is downward in the width range of the embankment, and the vertical displacement increases gradually with the construction of the embankment, and beyond the width range of the embankment, There is a certain amount of uplift on the base surface, and with the construction of the foundation surface, the vertical displacement uplift of the base surface and the compression boundary point are gradually far away from the central axis of the embankment. The horizontal displacement of the base surface is distributed as a parabola with an opening down during the construction of the dam, and the increasing speed of the horizontal displacement within the range of 9 m from the central axis of the dam is relatively small. With the increase of section depth, the vertical displacement decreases gradually, and the vertical displacement of the same depth increases rapidly during the filling process. The horizontal displacement increases first and then decreases with the depth of the section, and the horizontal displacement at the same depth of the section increases with the filling. Using Hardening-Soil model to calculate the excess pore water pressure of soil mass dissipates rapidly, the pore water pressure after one year is 2.7 KN / m ~ (2), and the result of Mohr Coulomb model is 5.2 KN / m ~ (2), which is smaller than the measured value 4.4KN/m2. With the increase of the distance from the center axis of the dam, the axial force of the bag body decreases gradually, and the axial force of the bag body of the base surface increases slightly with the construction of the dam. And the increasing speed of axial force decreases gradually.) based on the finite element method of strength reduction, it is found that the reinforced soil strip method is not suitable to calculate the stability of the reinforced earth.
【學位授予單位】：遼寧工程技術(shù)大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U656

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本文編號：1989769