本文關(guān)鍵詞：酸雨環(huán)境下砂巖腐蝕過程及物理力學(xué)特性研究　出處：《西安建筑科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 砂巖 溶蝕速率 縱波波速 CT數(shù)

【摘要】：近些年來,隨著國民經(jīng)濟(jì)建設(shè)的快速發(fā)展,人類生產(chǎn)生活對環(huán)境造成了嚴(yán)重的損害,環(huán)境污染是目前環(huán)境巖土工程學(xué)科面臨需要重點(diǎn)研究的課題。大氣中酸性氣體急劇增加,從而導(dǎo)致酸雨產(chǎn)生,酸性環(huán)境會嚴(yán)重影響巖石的物理力學(xué)性質(zhì)。為此,本文采用PH=2、PH=3.5及PH=5的HCl溶液模擬室內(nèi)加速腐蝕試驗(yàn),用定義的物理量及超聲波檢測技術(shù)獲得的物理力學(xué)參數(shù),定量分析巖樣腐蝕過程中物理化學(xué)性質(zhì)的變化規(guī)律,通過CT圖像及CT數(shù)分析物理力學(xué)參數(shù)變化對巖樣化學(xué)損傷的影響,得到如下研究成果:1.在不同濃度HCl溶液的腐蝕過程中,巖樣的質(zhì)量變化、溶蝕速率和孔隙率變化表現(xiàn)出明顯的階段性。0~30及70~90天隨著質(zhì)量損失率的增加孔隙率迅速增加,30~60天質(zhì)量損失率減小,孔隙率增加緩慢,每個階段的溶蝕速率呈現(xiàn)先增后減的趨勢。2.運(yùn)用超聲波檢測技術(shù)對浸泡在不同濃度HCl溶液的巖樣進(jìn)行進(jìn)行測試,發(fā)現(xiàn)不同腐蝕階段濕巖樣的縱波波速和振幅變化較為明顯,其變化規(guī)律為:0~30天,波速變化率較大,之后波速增加緩慢,70~90天波速趨于穩(wěn)定。3.對不同濃度HCl溶液中H+、Na+、Ca2+、K+、Mg2+等陽離子的跟蹤觀測表明,初始濃度不同的HCl溶液中PH值隨腐蝕時間的增加而增加,陽離子溶解速率隨HCl溶液濃度變化呈現(xiàn)階段性特征。第一階段PH=2的HCl溶液中Na+溶解速率在初期最大為264.78 mol/d,PH=3.5及PH=5的HCl溶液中Na+溶解速率在中期達(dá)到最大值;PH=2的HCl溶液中Ca2+溶解速率最大為489.50 mol/d,分別是PH=3.5及PH=5的HCl溶液中Ca2+溶解速率的5倍和4倍。4.單軸壓縮試驗(yàn)發(fā)現(xiàn),腐蝕后的巖樣的應(yīng)力-應(yīng)變曲線上非線性段增加,巖樣發(fā)生整體破壞的時間延長,且化學(xué)腐蝕使巖樣抗壓強(qiáng)度、彈性模量減小,力學(xué)性能劣化。CT掃描結(jié)果發(fā)現(xiàn),溶液的腐蝕作用使巖樣發(fā)生化學(xué)損傷,不同掃描層面和測量區(qū)域內(nèi)的損傷變量呈現(xiàn)區(qū)域性特征,中間掃描層損傷變量最小。
[Abstract]:In recent years, with the rapid development of national economic construction, human production and life have caused serious damage to the environment. Environmental pollution is a subject that needs to be studied in the field of environmental geotechnical engineering at present. The acid gas in the atmosphere increases rapidly, which leads to acid rain, and acid environment will seriously affect the physical and mechanical properties of rock. In this paper, the indoor accelerated corrosion test was simulated by HCl solution of PH2 + PH3. 5 and PH=5, and the physical and mechanical parameters obtained by using the defined physical quantity and ultrasonic testing technique were used to simulate the indoor accelerated corrosion test. The changes of physical and chemical properties of rock samples during corrosion are quantitatively analyzed. The effects of the changes of physical and mechanical parameters on the chemical damage of rock samples are analyzed by CT images and CT numbers. The following results are obtained: 1. The quality of rock samples changes during the corrosion process of HCl solution with different concentrations. The change of dissolution rate and porosity showed that the mass loss rate decreased rapidly with the increase of mass loss rate at 30 ~ 30 and 70 ~ 90 days, and the mass loss rate decreased at 30 ~ 60 days with the increase of mass loss rate. The porosity increased slowly and the dissolution rate of each stage increased first and then decreased. 2. Ultrasonic testing technique was used to test rock samples immersed in different concentrations of HCl solution. It is found that the variation of longitudinal wave velocity and amplitude of wet rock samples in different corrosion stages is obvious, and the variation rule is: 0 ~ 0 ~ 30 days, the rate of change of wave velocity is large, and then the wave velocity increases slowly. The wave velocities of 70 ~ 90 days tend to be stable .3.The trace observation of H ~ (2 +) Na ~ (2 +) Ca ~ (2 +) Ca ~ (2 +) K ~ (2 +) mg _ (2) ions in different concentrations of HCl. The PH value of HCl solution with different initial concentration increases with the increase of corrosion time. The dissolution rate of cationic ions varies with the concentration of HCl solution. In the first stage, the dissolution rate of Na in HCl solution of PH=2 is 264.78 mol/d. The dissolution rate of Na in HCl solution of PH=3.5 and PH=5 reached the maximum in the middle phase. The maximum dissolution rate of Ca2 in HCl solution of PH=2 is 489.50 mol/d. The dissolution rate of Ca2 in HCl solution of PH=3.5 and PH=5 is 5 times and 4 times of that in HCl solution, respectively. Uniaxial compression test shows that the nonlinear section of stress-strain curve of corroded rock samples increases. The whole damage time of rock sample is prolonged, and chemical corrosion reduces the compressive strength and elastic modulus of rock sample, and the mechanical property deterioration. Ct scan results show that the chemical damage of rock sample is caused by solution corrosion. The damage variables in different scan planes and measured areas showed regional characteristics, while the middle scan layers showed the smallest damage variables.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU45;X141

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