發(fā)布時(shí)間：2018-12-05 14:18

【摘要】：本文依托工程為通古勒格淖爾至額爾克哈什哈公路,該項(xiàng)目位于騰格里沙漠,沙漠區(qū)域內(nèi),沙丘、鹽沼、山地、湖盆、草灘及平原交錯(cuò)分布,路線穿過(guò)湖盆地帶,較多分布為鹽漬化軟土。此外,沙漠地區(qū)公路多設(shè)計(jì)為低路堤,受交通荷載的影響更甚。本文通過(guò)現(xiàn)場(chǎng)調(diào)查與室內(nèi)試驗(yàn)對(duì)公路沿線鹽漬土分布特征進(jìn)行了研究,得到了沿線鹽漬土分區(qū)圖;建立現(xiàn)場(chǎng)試驗(yàn)路,在施工期與運(yùn)營(yíng)期對(duì)路基進(jìn)行沉降觀測(cè),結(jié)果表明,除去異常數(shù)據(jù)斷面,采用風(fēng)積沙、砂礫換填處治,沉降速率較小,沉降穩(wěn)定,滿足工程建設(shè)要求。根據(jù)本項(xiàng)目實(shí)際,采用簡(jiǎn)諧荷載模擬交通荷載,以分布帶的方式實(shí)現(xiàn)荷載移動(dòng),建立了移動(dòng)簡(jiǎn)諧荷載下三維路堤模型,對(duì)風(fēng)積沙換填處治、車輛滿載和車速40km/h下的路基動(dòng)力響應(yīng)進(jìn)行了數(shù)值計(jì)算,分析了豎向位移、應(yīng)力沿深度變化的規(guī)律以及動(dòng)應(yīng)力的滯后效應(yīng),得到了動(dòng)力時(shí)程曲線,結(jié)合路基工作區(qū)概念,確定了該工況下風(fēng)積沙路基動(dòng)力響應(yīng)影響深度約為1.9m。與上文同位置的地基換填深度對(duì)比,進(jìn)一步驗(yàn)證了試驗(yàn)路段的處治方案是合理的�？紤]超載、地基加固區(qū)材料及行車速度等因素,單因素變量控制進(jìn)行數(shù)值計(jì)算。超載時(shí),動(dòng)力響應(yīng)影響深度遠(yuǎn)大于滿載下的1.9m,從豎向塑性應(yīng)變區(qū)域可以看出,超載可能對(duì)路基及邊坡造成很大的破壞;采用砂礫處治時(shí),砂礫材料改善了上部路基的變形特性;動(dòng)荷載的作用時(shí)間與幅值是動(dòng)力響應(yīng)的主要影響因素,豎向動(dòng)位移、等效塑性應(yīng)變值主要受作用時(shí)間的影響;車速增大引起了更大的動(dòng)荷載幅值,導(dǎo)致豎向動(dòng)應(yīng)力的波動(dòng)增長(zhǎng)劇烈,豎向塑性應(yīng)變?cè)酱�。隨著車速增大,動(dòng)力響應(yīng)愈加劇烈,隨后變?nèi)?對(duì)應(yīng)車速下,動(dòng)力響應(yīng)有一個(gè)峰值,本文中108 km/h時(shí),動(dòng)力響應(yīng)最為明顯。與已有的試驗(yàn)研究成果進(jìn)行了對(duì)比,結(jié)果表明,本文有限元模型數(shù)值計(jì)算結(jié)果在規(guī)律上是可靠的,得到的結(jié)論與試驗(yàn)段監(jiān)測(cè)結(jié)果可以為其他類似地區(qū)鹽漬化軟土地基及低路堤設(shè)計(jì)施工作參考。
[Abstract]:The project is located in the Tenggri desert, desert area, sand dune, salt marsh, mountain, lake basin, grass beach and plain. The project is located in Tenggri desert, desert area, sand dune, salt marsh, mountain, lake basin, grass beach and plain. Most of them are salinized soft soil. In addition, the highway in desert area is mostly designed as low embankment, which is more affected by traffic load. In this paper, the distribution characteristics of salinized soil along the highway are studied through field investigation and indoor test, and the zoning map of saline soil along the highway is obtained. The site test road was set up and the subgrade settlement was observed during the construction period and the operation period. The results showed that apart from the abnormal data section, the sand and gravel were replaced by wind sand, the settlement rate was small, the settlement was stable, and the engineering construction requirement was satisfied. According to the actual situation of the project, the traffic load is simulated by harmonic load, and the load is moved by distributed belt. A three-dimensional embankment model under moving harmonic load is established, and the sand is replaced and filled. The dynamic response of roadbed under full load and speed 40km/h is numerically calculated. The law of vertical displacement, the variation of stress along depth and the hysteresis effect of dynamic stress are analyzed. The dynamic time history curve is obtained and combined with the concept of subgrade working area. The influence depth of dynamic response of wind-sand roadbed under this condition is about 1.9 m. Compared with the above-mentioned foundation replacement depth, it is further proved that the treatment scheme of the test section is reasonable. The single factor variable control is used to calculate the factors such as overload, material in the foundation reinforcement area and the driving speed. The influence depth of dynamic response under overload is much greater than that of 1.9 m under full load. It can be seen from the vertical plastic strain region that overload may cause great damage to roadbed and slope. When the gravel is treated with sand and gravel, the deformation characteristics of the upper roadbed are improved, the time and amplitude of the dynamic load are the main influencing factors of the dynamic response, the vertical dynamic displacement and the equivalent plastic strain value are mainly affected by the action time. The larger amplitude of dynamic load is caused by the increase of speed, and the fluctuation of vertical dynamic stress increases sharply. The larger the vertical plastic strain is, the larger the vertical plastic strain is. With the increase of the vehicle speed, the dynamic response becomes more intense and then weakens. The dynamic response has a peak value at the corresponding speed, and the dynamic response is the most obvious at 108 km/h in this paper. Compared with the existing experimental results, the results show that the numerical results of the finite element model in this paper are reliable in law. The conclusions obtained and the monitoring results of the test section can be used as reference for the design and construction of salinized soft soil foundation and low embankment in other similar areas.
【學(xué)位授予單位】：長(zhǎng)安大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：U416.1

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本文編號(hào)：2365245