本文關(guān)鍵詞： 路基工程 風(fēng)積沙路基 含水率 含鹽量 模型試驗(yàn) 水鹽遷移　出處：《交通運(yùn)輸工程學(xué)報(bào)》2017年03期 　論文類型：期刊論文

【摘要】：以沙漠區(qū)風(fēng)積沙路基土為依托,檢測(cè)了典型路面病害路段不同深度試樣的化學(xué)成分,基于土水勢(shì)原理,分析了路基內(nèi)鹽分與水分的遷移特點(diǎn);以95%的壓實(shí)度分層填筑土樣,采用自制試驗(yàn)裝置測(cè)試模型土柱的含水率與導(dǎo)電率,研究了最佳含水率條件下溫度梯度對(duì)路基內(nèi)水鹽遷移規(guī)律的影響。研究結(jié)果表明:病害路段路基土為細(xì)沙,基層與路基土含鹽成分均以可溶性硫酸鈉與鉀鹽為主,在-6℃~0℃會(huì)形成Na2SO4·10H2O,發(fā)生體積膨脹,當(dāng)遇到外界水分的進(jìn)入,就會(huì)加劇路基土鹽脹和路面隆起破壞;路基壓實(shí)一周后,土樣5cm深度處含水率降低了1%~2%,硫酸根含量降低了0.05%~0.06%,在35cm深度處含水率升高了0.5%~0.8%,硫酸根含量降低了0.12%~0.14%,在重力勢(shì)與壓實(shí)的雙重作用下,均質(zhì)土體出現(xiàn)快速且明顯的水鹽分層現(xiàn)象;在外界溫度作用下,土樣25cm深度范圍內(nèi)溫差為20℃~30℃,超過25cm深度范圍,溫差約為1℃,隨著深度增加,溫度梯度變化量逐漸減小,最終趨于0;風(fēng)積沙路基內(nèi)部水鹽分布隨深度先降低后增加,水鹽場(chǎng)隨深度分布呈現(xiàn)"對(duì)勾"狀規(guī)律;風(fēng)積沙路基內(nèi)部的水鹽遷移是由氣、液兩態(tài)混合作用的結(jié)果,在高溫作用下,路基頂面10cm范圍內(nèi)水氣遷移占據(jù)了主要的遷移方式,而在10cm以下主要由細(xì)沙構(gòu)成的風(fēng)積沙內(nèi)無法形成有效的毛細(xì)水上升孔道,水分主要以薄膜水的形式進(jìn)行遷移,在降溫作用下,液態(tài)水?dāng)y帶鹽分上升,在路基頂面形成鹽分積聚現(xiàn)象。
[Abstract]:Based on the wind-accumulated sand subgrade soil in desert area, the chemical composition of different depth samples of typical pavement damage section was detected. Based on the principle of soil and water potential, the characteristics of salt and moisture migration in roadbed were analyzed. The soil sample was packed with 95% compaction degree, and the moisture content and conductivity of the model soil column were measured by self-made test device. The effect of temperature gradient on the migration of water and salt in subgrade was studied under the condition of optimum moisture content. The results show that the subgrade soil in the diseased section is fine sand. Na2SO4 路10H _ 2O is formed at 6 鈩，

本文編號(hào)：1472805