本文選題：黃土 + 滑坡��； 參考：《西北農(nóng)林科技大學(xué)》2013年碩士論文

【摘要】：在我國，黃土和黃土狀土廣泛分布，總面積約為64萬m2。黃土滑坡地質(zhì)災(zāi)害頻繁發(fā)生，以其大規(guī)模、強(qiáng)危害、難預(yù)測、難治理等特點(diǎn)嚴(yán)重威脅著人民生命財(cái)產(chǎn)安全，限制著黃土地區(qū)經(jīng)濟(jì)和社會(huì)發(fā)展。另外，黃土高原普遍存在坡面侵蝕問題，主要發(fā)生在降雨較多的6—9月，黃土坡面會(huì)遭受嚴(yán)重破壞，進(jìn)一步引發(fā)水土環(huán)境惡化及土壤養(yǎng)分流失，降低土地生產(chǎn)力。降雨等引發(fā)的水分入滲對邊坡的破壞作用是顯而易見的，坡面沖蝕也是由降雨引起，鑒于此，為進(jìn)一步保障人民生命財(cái)產(chǎn)安全，本文將開展針對降雨這一主要誘因?qū)S土滑坡和坡面侵蝕的影響的試驗(yàn)研究。 本文自行研制人工降雨裝置，并建立了黃土邊坡的室內(nèi)模型，所用黃土土料取自陜西楊凌。通過人工降雨條件下黃土滑坡及裸坡坡面形態(tài)變化的試驗(yàn)研究，，利用水分傳感器、應(yīng)力傳感器、示蹤點(diǎn)、數(shù)碼拍攝等綜合監(jiān)測，觀察了強(qiáng)降雨條件下黃土滑坡的發(fā)生發(fā)展過程以及坡面形態(tài)的變化情況。試驗(yàn)的主要內(nèi)容及結(jié)論如下： （1）通過在邊坡內(nèi)部埋設(shè)的水分傳感器獲得坡體內(nèi)部實(shí)時(shí)含水率，并在有機(jī)玻璃一側(cè)觀察濕潤峰情況。由此可知，水分入滲速率隨時(shí)間變化由快到慢，坡頂?shù)乃秩霛B速率始終大于坡面的；水分徑流量和入滲量的比值隨時(shí)間先增大再減小最終趨于穩(wěn)定；坡體內(nèi)部含水率由上到下依次開始增大，其值增大到一定水平后趨于平穩(wěn)，標(biāo)志著該位置土體近似飽和，模型發(fā)生滑坡時(shí)最大體積含水率約為41%~44%。 （2）60°模型內(nèi)部埋設(shè)微型壓力盒測量不同位置的應(yīng)力值�？芍�，某一位置的應(yīng)力與其深度有關(guān)，深度越深應(yīng)力越大；應(yīng)力發(fā)展與時(shí)間有關(guān)，累計(jì)時(shí)間在t=400min~700min之間時(shí)應(yīng)力值波動(dòng)最大，據(jù)此可知該時(shí)間段有可能是滑坡形成的關(guān)鍵期。 （3）通過示蹤點(diǎn)、小紅旗、棉線等實(shí)現(xiàn)位移監(jiān)測并對表面現(xiàn)象如裂縫等進(jìn)行觀察記錄�？芍�，坡體有向下和向前兩個(gè)方向的位移，坡頂下方位移方向與豎向所成角度約為0~10°，最大位移約10cm；坡面下方位移方向與豎向所成角度約為30°~60°，最大位移約15cm；降雨過程中坡頂首先產(chǎn)生貫通的拉裂縫，水分進(jìn)一步入滲后坡體內(nèi)部產(chǎn)生局部微小豎向裂縫。 （4）利用數(shù)碼設(shè)備記錄邊坡整體變化和坡面形態(tài)變化等，以45°模型試驗(yàn)為例可知，其坡面侵蝕經(jīng)歷了“片蝕—溝蝕—溝間坡面面蝕向深切和側(cè)蝕發(fā)展”的過程，后期形成較大沖蝕溝并且溝岸發(fā)生崩塌；坡面因受侵蝕呈整體下降趨勢；降雨使得坡趾處土體飽和程度較高，小型滑塌自下而上發(fā)展，邊坡土體的坡面崩滑位置逐漸向上推移，最終發(fā)生大規(guī)模坡面崩滑。
[Abstract]:Loess and loess soil are widely distributed in China, with a total area of about 640000 m2. The frequent occurrence of loess landslide geological hazard is a serious threat to the safety of people's life and property and restricts the economic and social development of loess area because of its large scale, strong harm, hard to predict, difficult to manage and so on. In addition, slope erosion is a common problem in the Loess Plateau, which mainly occurs in the June to September rainfall. The loess slope will suffer serious damage, which will further lead to the deterioration of soil and water environment and soil nutrient loss, and reduce the land productivity. The effect of water infiltration caused by rainfall on the slope is obvious, and the erosion of the slope is also caused by rainfall. In view of this, in order to further ensure the safety of people's lives and property, In this paper, the influence of rainfall on loess landslide and slope erosion will be studied. In this paper, the artificial rainfall device is developed, and the indoor model of loess slope is established. The loess soil material is taken from Yang Ling of Shaanxi province. Through the experimental study on the morphological change of loess landslide and bare slope under artificial rainfall, the comprehensive monitoring is made by using water sensor, stress sensor, tracer point, digital photography and so on. The occurrence and development process of loess landslide and the change of slope shape were observed under the condition of heavy rainfall. The main contents and conclusions of the experiment are as follows: 1) the real time moisture content of the slope is obtained by the moisture sensor embedded in the slope and the wet peak is observed on the side of organic glass. It can be seen that the water infiltration rate changes from fast to slow with time, the water infiltration rate at the top of the slope is always larger than that on the slope, and the ratio of water runoff and infiltration volume increases first with time and then decreases and then tends to stabilize. The moisture content of the slope begins to increase from top to bottom, and the value increases to a certain level, which indicates that the soil is approximately saturated in this position. The maximum volume water content of the model is about 41 / 44 when the landslide occurs. The stress values of different positions are measured by embedding a micro pressure box inside the model. It can be seen that the stress in a certain position is related to its depth, the deeper the stress is, the greater the stress is, and the stress development is related to time, and the stress value fluctuates most when the cumulative time is between t=400min~700min. It can be concluded that this time period may be the key period of landslide formation. (3) displacement monitoring is realized by tracing points, small red flags, cotton thread and so on, and surface phenomena such as cracks are observed and recorded. It can be seen that there are downward and forward displacement in the slope, the angle between the displacement direction and the vertical direction is about 010 擄, the maximum displacement is about 10 cm, the angle between the direction and the vertical direction is about 30 擄and 60 擄, the maximum displacement is about 15 cm. In the process of rainfall, the top of the slope first produces a through pull crack, and after the water is further infiltrated, there are local tiny vertical cracks in the slope body. 4) the digital equipment is used to record the overall change of the slope and the change of the slope surface shape, etc. Taking the 45 擄model test as an example, it can be seen that the slope erosion has experienced the process of "deep erosion and lateral erosion development on the slope between the sheet erosion and the gully", which formed a large erosion trench and collapsed in the gully bank in the late stage, and the slope surface showed an overall downward trend because of the erosion. Rainfall makes the soil saturation degree is higher at the toe of the slope. The small landslide develops from the bottom to the top, and the landslide position of the slope soil gradually moves upward, and finally a large scale slope collapse occurs.
【學(xué)位授予單位】：西北農(nóng)林科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：TU411;TU444

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