本文選題：柔性加筋土復合體　切入點：室內(nèi)試驗　出處：《武漢理工大學》2014年碩士論文

【摘要】：有研究表明，土工合成材料加筋的高壓實度粒料土，如果加筋層間距足夠小，則受壓時筋-土界面幾乎不產(chǎn)生相對位移，可看成是一種復合材料。這里將具備此種性質(zhì)的加筋土稱為柔性加筋土復合體，由其形成的結(jié)構(gòu)物稱為加筋土復合體結(jié)構(gòu)。一些試驗表明，加筋土復合體結(jié)構(gòu)具有承載力高，變形小，自穩(wěn)性好，抗震性能優(yōu)良，工程成本低等優(yōu)良工程特性，所以適合于用來修建具有高抗震性能的柔性橋臺、擋土墻、加筋陡坡等支承結(jié)構(gòu)，具有廣闊的應用前景。但相關(guān)的研究還很少，以致在加筋土復合體的形成機理、形成條件、力學特性等基本理論問題還很不清楚，需要進行系統(tǒng)的研究，以便將來在工程實踐中能得到推廣應用。 有鑒于此，本文采用試驗與數(shù)值分析相結(jié)合的手段對柔性加筋土復合體的力學性能和變形特性進行了初步研究。分別采用室內(nèi)無側(cè)限抗壓強度試驗和數(shù)值模擬試驗，探討了加筋材料種類、加筋層間距、土的類別和壓實度等對柔性加筋土復合體的抗壓強度、變形特性的影響規(guī)律。根據(jù)試驗結(jié)果，利用FLAC3D軟件建立了數(shù)值分析模型，，對加筋土路堤邊坡穩(wěn)定性及其影響因素進行了分析。論文得到以下主要結(jié)論： （1）加筋土復合體抗壓強度和抗壓剛度都隨加筋層間距的減小或者壓實度的提高而增大。 （2）柔性加筋土復合體的應力-應變形態(tài)受加筋層間距的影響較大，隨加筋層間距的逐漸減小，其應力-應變曲線由應變軟化型逐漸向應變硬化型轉(zhuǎn)變。這說明在一定條件下，當加筋層間距小于某一臨界值時，加筋土的變形特性會發(fā)生質(zhì)的變化。該臨界值也許就是普通加筋土過渡到加筋土復合體的分界點，因此研究該臨界值的影響因素和影響規(guī)律，進而研究該臨界值的確定方法是值得進一步研究的重要課題。 （3）基于上述觀點，作者對大尺寸土工格柵加筋粒料土試件進行了無側(cè)限壓縮數(shù)值模擬試驗，其結(jié)果表明，對于加筋層間距小到30cm的加筋土試件，當壓縮量大于1.5cm后，其軸向壓力隨著壓縮變形的增大呈直線增加，說明間距足夠小時，加筋土表現(xiàn)出了類似于連續(xù)固體介質(zhì)的復合材料特性。 （4）與未加筋土邊坡相比，加筋顯著提高了陡邊坡的穩(wěn)定性且具有更大的安全儲備，加筋土邊坡的安全系數(shù)隨著加筋層間距增大或者筋材長度減小而減小，同未加筋土邊坡一樣，填料特性對加筋土邊坡穩(wěn)定性有重要的影響。
[Abstract]:Some studies have shown that if the spacing of the reinforced layer is small enough, the interface between the reinforcement and the soil can hardly produce relative displacement when the geotextile is reinforced by the geotextile. The reinforced soil with this property is called flexible reinforced soil complex, and the structure formed by it is called reinforced soil complex structure. Some tests show that the reinforced soil complex structure has high bearing capacity. Small deformation, good self-stability, good seismic performance, low engineering cost and other excellent engineering characteristics, so it is suitable for building flexible abutment, retaining wall, reinforced steep slope and other supporting structures with high seismic performance. It has a broad application prospect, but the related research is still few, so the basic theoretical problems such as formation mechanism, forming conditions, mechanical properties of reinforced soil complex are not clear, so it is necessary to carry out systematic research. In order to be popularized and applied in engineering practice in the future. In this paper, the mechanical properties and deformation characteristics of flexible reinforced soil complex are studied by means of the combination of test and numerical analysis. The indoor unconfined compressive strength test and numerical simulation test are used respectively. The effects of the type of reinforced material, the spacing of stiffened layer, the type of soil and the compaction degree on the compressive strength and deformation characteristics of the flexible reinforced soil complex are discussed. Based on the test results, a numerical analysis model is established by using FLAC3D software. The stability of reinforced embankment slope and its influencing factors are analyzed. The main conclusions are as follows:. 1) the compressive strength and stiffness of the reinforced soil complex increase with the decrease of the reinforcement layer spacing or the increase of the compaction degree. (2) the stress-strain pattern of the flexible reinforced soil complex is greatly affected by the spacing of the reinforced layer, and the stress-strain curve changes from the strain softening type to the strain hardening type with the decreasing of the reinforced layer spacing, which indicates that under certain conditions, the stress-strain curve of the composite is changed gradually from the strain softening type to the strain hardening type. When the spacing of reinforced soil is less than a certain critical value, the deformation characteristics of reinforced soil will change qualitatively. This critical value may be the dividing point of the transition of common reinforced soil to reinforced soil complex, so the influencing factors and law of the critical value are studied. The method of determining the critical value is an important subject worthy of further study. (3) based on the above viewpoint, the numerical simulation tests of the large size geogrid reinforced granular soil specimens are carried out. The results show that for the reinforced soil specimens with small reinforced layer spacing as small as 30cm, when the compression amount is greater than 1.5cm, The axial pressure increases in a straight line with the increase of compression deformation, indicating that the reinforced soil exhibits a composite property similar to that of a continuous solid medium when the spacing is small enough. Compared with the unreinforced soil slope, the reinforced soil slope has significantly improved the stability of the steep slope and has a greater safety reserve. The safety factor of the reinforced soil slope decreases with the increase of the reinforcement layer spacing or the decrease of the reinforcement material length, just like the unreinforced soil slope. The characteristics of fillers have an important effect on the stability of reinforced soil slope.
【學位授予單位】：武漢理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U416.1

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