本文選題：人工凍結(jié)鹽漬土　切入點(diǎn)：單軸壓縮強(qiáng)度　出處：《安徽理工大學(xué)》2014年碩士論文

【摘要】：鹽漬土本身的特殊性質(zhì)對(duì)土壤以及工程建設(shè)都具有較大的危害,且高寒地區(qū)鹽漬土的道路計(jì)算與設(shè)計(jì)牽涉了更為復(fù)雜的地質(zhì)條件和應(yīng)力狀態(tài),原有的凍融土力學(xué)概念已不能或完全不能適用于工程實(shí)踐。本文主要通過室內(nèi)試驗(yàn)中的單軸壓縮、單軸蠕變和三軸剪切試驗(yàn)來研究?jī)鼋Y(jié)鹽漬土的力學(xué)特性及其本構(gòu)模型�？紤]了加載方式、加載速率、凍結(jié)溫度、易溶鹽含量、土的性質(zhì)、圍壓大小、試驗(yàn)應(yīng)力路徑等因素對(duì)含鹽凍土力學(xué)特性的影響。經(jīng)研究獲得以下結(jié)論： (1)單軸壓縮實(shí)驗(yàn)結(jié)果表明,加載速率、凍結(jié)溫度、易溶鹽含量、含水率等均對(duì)凍土的強(qiáng)度有很大的影響。加載速率增大、溫度降低、含水率增大均會(huì)在不同程度上使凍土強(qiáng)度增大,而含鹽量的提高則使凍土的強(qiáng)度降低。 (2)以單軸蠕變實(shí)驗(yàn)為基礎(chǔ),采用多元回歸法以及非線性擬合法獲得時(shí)間、溫度、易溶鹽含量對(duì)應(yīng)力應(yīng)變關(guān)系的蠕變本構(gòu)公式。 (3)通過三軸試驗(yàn)獲得不同溫度、不同圍壓、不同含鹽量的三軸剪切試驗(yàn)結(jié)果。結(jié)果表明不同條件下的應(yīng)力應(yīng)變關(guān)系曲線基本呈拋物線形狀。且隨著軸向應(yīng)變的增大,在軸向應(yīng)變?chǔ)拧?1.0%～7.5%)時(shí),主應(yīng)力差迅速增長(zhǎng),且此段曲線近似成直線形式,表現(xiàn)為一定得彈性性狀,則此時(shí)為含鹽凍土的彈性體。隨著軸向應(yīng)變的繼續(xù)增大,主應(yīng)力差的變化逐漸變小,此時(shí)凍土的應(yīng)力-應(yīng)變關(guān)系曲線呈明顯的非線性,為凍土的塑性體。 (4)本文以彈塑性模型中的修正劍橋模型為基礎(chǔ),通過含鹽凍土的三軸剪切特性的試驗(yàn)研究,確定模型參數(shù),提出并驗(yàn)證凍結(jié)鹽漬土的本構(gòu)模型。
[Abstract]:The special properties of saline soil have great harm to soil and engineering construction, and the road calculation and design of saline soil in alpine area involve more complicated geological conditions and stress state.The original concept of freeze-thaw soil mechanics can not or can not be applied to engineering practice.In this paper, the mechanical properties and constitutive model of frozen saline soil are studied by uniaxial compression, uniaxial creep and triaxial shear tests.The effects of loading mode, loading rate, freezing temperature, soluble salt content, properties of soil, confining pressure and experimental stress path on the mechanical properties of saline frozen soil were considered.The results of the study are as follows:1) the uniaxial compression test results show that loading rate, freezing temperature, soluble salt content and moisture content have great influence on the strength of frozen soil.With the increase of loading rate and the decrease of temperature, the strength of frozen soil is increased with the increase of moisture content, while the strength of frozen soil decreases with the increase of salt content.(2) based on uniaxial creep experiment, the creep constitutive formula of time, temperature and soluble salt content on stress-strain relationship is obtained by multivariate regression method and nonlinear fitting method.The triaxial shear test results of different temperature, confining pressure and salt content are obtained by triaxial test.The results show that the stress-strain curves are parabola under different conditions.With the increase of axial strain, the principal stress difference increases rapidly when the axial strain 蔚 鈮，

本文編號(hào)：1719784