本文選題：土工格室 + 土工格柵　； 參考：《東北林業(yè)大學》2013年博士論文

【摘要】：本研究以土工格室為研究對象,通過土工格室加筋土的抗彎承載特性和筋土界面特性的試驗研究,探討土上格室加筋土的加固機理。 本研究通過承載力室內(nèi)模型試驗,得到PIV畫像解析圖片,利用PIV畫像解析方法和數(shù)字圖像處理技術(shù),對地基內(nèi)部砂的運動,細觀結(jié)構(gòu)的圖像進行定量和定性分析,得出地基砂土在條形均布荷載作用下,加筋前后各項參數(shù)和各種應(yīng)力、應(yīng)變場的變化規(guī)律。在模型試驗中將變形量測系統(tǒng)用于分析加筋地基加載變形破壞的位移、地基內(nèi)部局部剪應(yīng)變場的圖像,用以研究加筋地基的破壞模式和破壞面發(fā)展機理。采用有限元模擬分析地基砂內(nèi)部的局部應(yīng)力狀態(tài),解析地基砂內(nèi)外部的應(yīng)力場、應(yīng)力路徑及內(nèi)力變化。本研究將基礎(chǔ)模型按照實際基礎(chǔ)同比例縮小進行加筋土界面特性的試驗研究實驗,利用拉拔試驗裝置和位移計測土體內(nèi)部位移連續(xù)變化進程,得到土工格室拉拔抵抗力產(chǎn)生的原理模式圖像和土工格柵位移與拉拔抵抗力的分布狀況圖像,比較分析土工格室和土工格柵的拉拔特性,研究土工格室和土工格柵的位移傳遞機制。通過靜承載力試驗和紙狀的壓力傳感器測定應(yīng)力分布,對補強機理、應(yīng)力分散效果進行探討。利用應(yīng)力測定系統(tǒng),研究加筋土的網(wǎng)兜效應(yīng)和抗彎剛性及應(yīng)力分散效果。最后通過現(xiàn)場簡易承載力試驗比較不同種類補強材料的補強效果,復核土工格室模型與原型的系統(tǒng)相似定理。 本研究利用以上方法,追蹤加筋土地基的漸進性變形與破壞過程,捕捉加筋土地基的變形模式、滑動剪切面位置形狀和剪切帶特征。為研究砂土在拉拔水平荷載下的全場位移和局部位移的產(chǎn)生、發(fā)展和演化特點進行了量測和定量分析。 PIV畫像解析表明無土工格室補強地基內(nèi)速度向量分布是在載荷板正下方往正中心方向運動顯著,速度大,表明載荷板正下方應(yīng)力集中,土工格室補強地基內(nèi)速度向量分布是在載荷板正下方出現(xiàn)橫方向的運動,速度小且均勻,表明應(yīng)力集中現(xiàn)象被沖散。變形量測系統(tǒng)分析表明純砂或無補強時地基內(nèi)部砂在剪切過程中,最大剪應(yīng)變的方向均在約10°的破裂線上,而土工格柵加筋土剪應(yīng)變等值線,即最大剪應(yīng)變幾乎發(fā)生在水平方向上,且該水平面與筋材的布置十分一致。有限元模擬分析表明加筋砂土地基內(nèi)部的高補強效果在局部應(yīng)力狀態(tài)已接近破壞狀態(tài),且破壞區(qū)域擴散后才表現(xiàn)出來。加筋土界面特性研究表明土工格柵應(yīng)變軟化來得快,應(yīng)變軟化開始直接進入到相當小的殘留強度狀態(tài)；而土工格室是應(yīng)變軟化來得遲,先顯示出稍高的最大抵抗力,以后應(yīng)變軟化較短,最后表現(xiàn)出相當大的殘留強度。土工格室的內(nèi)部位移是從墻壁近旁開始向后方進行傳播,其進展性土工格柵比土工格室更顯著。應(yīng)力擴散試驗表明土工格柵、土工格室加筋土地基的應(yīng)力曲線在中心附近的尖頂分布,而土工格柵配合土工格室加筋土地基的應(yīng)力曲線在中心附近較寬闊范圍內(nèi)緩慢分布,即后者比前者應(yīng)力擴散效果好。土工格柵配合土工格室加筋土地基承載力較大,而碎石作為填料使用時,土工格室碎石加筋土地基承載力比土工格柵配合土工格室加筋土地基承載力還大。 土工格室與土工格柵主要區(qū)別在于,前者因具有一定的厚度,固具有一定的抗彎能力,能有效擴散從上部結(jié)構(gòu)傳來的豎向應(yīng)力；同時發(fā)揮類似于“深基礎(chǔ)”的作用,大大提高地基的承載能力。 實驗結(jié)果表明,有限元數(shù)值模擬的細觀力學特性與土體的宏觀力學現(xiàn)象密切相關(guān),有限元法數(shù)值模擬技術(shù)分析研究加筋地基的承載力和變形特性是可行的。物理模型試驗PIV圖像的細觀結(jié)構(gòu)的變化特征,反應(yīng)了土體的宏觀力學響應(yīng)特性,說明了通過對土體的PIV細觀結(jié)構(gòu)變化來反應(yīng)土體破壞前后的強度和變形的可行性。通過對這兩種細觀觀測結(jié)果進行關(guān)聯(lián)性分析,同時與宏觀試驗結(jié)果進行對比分析,結(jié)果表明PIV圖像的細觀結(jié)構(gòu)的變化特征與宏觀力學響應(yīng)特性具有很好的一致性。 土工格室作為一種新型建筑材料具有良好適應(yīng)性(適應(yīng)多種填料)、良好的經(jīng)濟性(工程項目上應(yīng)用土工格室最多節(jié)約達30%的投資)及良好的穩(wěn)定性,土工格室工法能有效利用現(xiàn)場土質(zhì),減少土石方量,有效削減環(huán)境負荷,加快工程進度。對土工格室加筋結(jié)構(gòu)的作用機理的研究還有待深化,提出一種實用的工程設(shè)計計算方法是當務(wù)之急。
[Abstract]:In this study, the geotextile chamber was taken as the research object. Through the experimental study on the flexural bearing characteristics of the geotextile reinforced soil and the interface characteristics of the reinforced soil, the reinforcement mechanism of the reinforced soil on the soil lattice was discussed.
In this study, through the test of the bearing capacity indoor model, the PIV picture analytic picture is obtained. Using the PIV image analysis method and the digital image processing technology, the quantitative and qualitative analysis of the movement of sand in the foundation and the image of the meso structure is carried out, and the parameters and various stresses and strains before and after the reinforcement are obtained. In the model test, the deformation measurement system is used to analyze the displacement of the reinforced foundation loading deformation and failure, the local shear strain field image in the foundation, in order to study the failure mode of the reinforced foundation and the mechanism of the development of the failure surface. The stress field, stress path and internal force change of the section. The experimental research experiments are made to reduce the interface characteristics of reinforced earth with the basic model according to the actual basis. The principle pattern images and geotextiles of the pull out resistance of the geotextile room are obtained by using the drawing test device and the displacement meter to measure the continuous change process of the internal displacement of the soil. The distribution of the grid displacement and the drawing resistance is compared and analyzed. The transfer mechanism of the geomers and geogrids is studied. The displacement transmission mechanism of the geomers and geogrids is studied. The stress distribution is measured by the static bearing test and the paper pressure sensor. The reinforcement mechanism and the stress dispersion effect are discussed. The stress measurement system is used. The effect of net pocket and flexural rigidity and stress dispersion of reinforced soil are studied. Finally, the reinforcement effect of different kinds of reinforcement materials is compared through the field simple bearing capacity test, and the system similarity theorem of the geotextile room model and the prototype is reviewed.
In this study, the above method is used to track the progressive deformation and failure process of reinforced soil foundation, to capture the deformation mode of the reinforced soil foundation, the shape of the sliding shear surface and the characteristics of the shear band, and to study the development and evolution of the full field displacement and local displacement of the sand under the horizontal loading.
The analysis of PIV picture shows that the velocity vector distribution in the subsoil of the subsoil reinforcement is significant in the positive center direction under the load plate, and the velocity is large, which indicates the stress concentration under the load plate. The velocity vector distribution in the reinforcing foundation of the geotextile chamber is the horizontal movement under the load plate, which is small and uniform, indicating the stress set. The analysis of the deformation measurement system shows that the maximum shear strain is in the fracture line about 10 degrees during the shear process of the sand in pure sand or without reinforcement, and the shear strain equivalent line of the geogrid reinforced earth shear strain, that is, the maximum shear strain almost occurs in the horizontal direction, and the horizontal plane is in good agreement with the arrangement of the steel. The finite element simulation analysis shows that the high reinforcement effect in the reinforced sand soil foundation is close to the failure state in the local stress state, and only after the destruction of the regional diffusion. The study of the reinforced soil interface characteristics shows that the geogrid strain softening is faster and the strain softening begins to enter a fairly small residual strength state; and the geotextile chamber is in the geotextile chamber. It is the delay of strain softening, which shows a slightly higher maximum resistance first, the strain softening is shorter, and a considerable residual strength is shown at the end. The internal displacement of the geotextile chamber begins to propagate back from the wall near the wall, and its progressive geogrid is more obvious than the geotextile room. The stress diffusion test indicates that the geogrid and geotextile room are shown by the stress diffusion test. The stress curve of the reinforced soil foundation is distributed near the center, while the stress curve of the geogrid and the reinforced earth base of the geomer chamber is slowly distributed in the wider range near the center. That is, the latter is more effective than the former. The geogrid and the geogrid reinforced soil foundation have greater bearing capacity, and the gravel is used as a filler. The bearing capacity of geocell reinforced earth foundation is larger than that of geogrid reinforced geocell reinforced earth foundation.
The main difference between geotextile room and geogrid is that the former is able to effectively diffuse the vertical stress from the superstructure because of a certain thickness, and can effectively diffuse the vertical stress from the superstructure, and also plays a role similar to the "deep foundation", which greatly improves the bearing capacity of the foundation.
The experimental results show that the meso mechanical properties of the finite element numerical simulation are closely related to the macroscopic mechanical phenomena of the soil. It is feasible to analyze the bearing capacity and deformation characteristics of the reinforced foundation by the finite element method numerical simulation technique. The physical model test of the microstructure of the PIV images reflects the macroscopic mechanical response characteristics of the soil. The feasibility of reacting the strength and deformation of the soil before and after the soil failure is explained by the change of the PIV meso structure of the soil. The results of these two observations are analyzed and compared with the macroscopic test results. The results show that the variation characteristics of the mesoscopic structure of the PIV image and the macroscopic mechanical response characteristics are very good. Good consistency.
Geomer room, as a new type of building material, has good adaptability (suitable for many kinds of packing), good economy (up to 30% of the investment in geomer room on engineering projects) and good stability. Geotextile room method can effectively use the site soil, reduce soil Shi Fangliang, effectively reduce environmental load and speed up the project progress. The research on the mechanism of geocell reinforced structure needs to be deepened. It is imperative to propose a practical engineering design and calculation method.

【學位授予單位】：東北林業(yè)大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：TU470

【參考文獻】

相關(guān)期刊論文 前10條

1 楊曉華,俞永華;土工格室在太古公路路基不均勻沉降病害處治中的應(yīng)用[J];重慶交通學院學報;2004年05期

2 周志剛,張起森,鄭健龍;土工加筋材料性能研究綜述[J];長沙交通學院學報;2001年02期

3 楊和平;萬亮;譚波;;土工格柵拉拔試驗研究的現(xiàn)狀與發(fā)展[J];長沙交通學院學報;2006年01期

4 楊慶;張克;欒茂田;季大雪;;土工格柵加筋砂土地基性能模型試驗研究[J];大連理工大學學報;2006年03期

5 馬玉靜;魏然;;土工格柵加筋土擋墻工作性能參數(shù)的有限元分析[J];國防交通工程與技術(shù);2009年01期

6 楊曉華,晏長根,謝永利;黃土路堤土工格室護坡沖刷模型試驗研究[J];公路交通科技;2004年09期

7 周春兒;何光春;龍麗吉;;臺階式土工格柵加筋土擋墻結(jié)構(gòu)優(yōu)化設(shè)計[J];河海大學學報(自然科學版);2008年05期

8 趙明華,陳艷平,陳昌富,楊宇;土工格室+碎石墊層結(jié)構(gòu)體的穩(wěn)定性分析[J];湖南大學學報(自然科學版);2003年02期

9 何友芳;尹光志;張東明;;土工格柵與銅礦尾礦界面作用特性的實驗研究[J];重慶建筑大學學報;2006年02期

10 楊曉華,戴鐵丁,許新樁;土工格室在鐵路軟弱基床加固中的應(yīng)用[J];交通運輸工程學報;2005年02期

，

本文編號：1816688