【摘要】：巖土體抗剪強(qiáng)度是分析評價(jià)斜坡穩(wěn)定性的關(guān)鍵指標(biāo)。為了弄清可溶鹽在黃土抗剪特性中的作用程度及控制機(jī)制,以蘭州重塑黃土為對象,基于直剪試驗(yàn),研究了黃土抗剪強(qiáng)度及其參數(shù)在不同溶濾次數(shù)下的變化特征。結(jié)果顯示,可溶鹽對非飽和黃土抗剪強(qiáng)度及黏聚力具有明顯非線性弱化作用,而對內(nèi)摩擦角的影響則相對微弱。其中,抗剪強(qiáng)度與黏聚力隨可溶鹽的變化規(guī)律存在臨界分段現(xiàn)象,其降低幅度在溶濾1次時(shí)達(dá)到最大值,在溶濾5次后近似于0;而降低速率以易溶鹽含量2 620 mg/100 g干土為分界值,呈先快后慢的變化特征。上述關(guān)系的內(nèi)在機(jī)制是,在溶濾初始階段,黃土抗剪特性弱化主要源于易溶鹽與部分難溶鹽分解;隨溶濾次數(shù)增加,則更多依賴于易溶鹽分解與基質(zhì)吸力減弱。
[Abstract]:The shear strength of rock and soil is the key index to analyze and evaluate the slope stability. In order to understand the effect and control mechanism of soluble salt on the shear resistance of loess, taking Lanzhou remolded loess as an example, based on the direct shear test, the variation characteristics of loess shear strength and its parameters under different dissolved filtration times were studied. The results show that the soluble salt has obvious nonlinear weakening effect on the shear strength and cohesion of unsaturated loess, but the influence on the angle of internal friction is relatively weak. Among them, the shear strength and cohesion with the variation of soluble salt have critical segmental phenomenon, and the decrease of shear strength and cohesion reaches the maximum at the first time of solubilization. After 5 times of leaching, the rate of reduction was approximately 0, and the decreasing rate was at the boundary value of 2620 mg/100 g dry soil, which showed the characteristics of first quick change and then slow change. The intrinsic mechanism of the above relationship is that in the initial stage of dissolved filtration, the weakening of shear resistance of loess is mainly due to the decomposition of soluble salt and part of insoluble salt, and with the increase of leaching times, it is more dependent on the decomposition of soluble salt and the weakening of matrix suction.
【作者單位】： 華北水利水電大學(xué)資源與環(huán)境學(xué)院;中國地質(zhì)大學(xué)(北京)水資源與環(huán)境學(xué)院;
【基金】：國家自然科學(xué)基金項(xiàng)目(No.41372260,No.41402269) 河南省科技創(chuàng)新人才計(jì)劃(No.154100510006) 華北水利水電大學(xué)高層次人才科研啟動(dòng)金(No.40432)~~
【分類號】：TU444

【相似文獻(xiàn)】

相關(guān)期刊論文 前2條

1 嚴(yán)紹軍;方云;劉俊紅;譚松娥;;可溶鹽對云岡石窟砂巖劣化試驗(yàn)及模型建立[J];巖土力學(xué);2013年12期

2 歐孝奪;周東;曹凈;吳恒;;黏土孔隙可溶鹽組份對黏土結(jié)構(gòu)熱 力學(xué)行為的影響[J];巖土工程學(xué)報(bào);2009年03期

，

本文編號：2279619