本文選題：斷裂韌度　切入點(diǎn)：化學(xué)損傷　出處：《重慶大學(xué)》2015年碩士論文

【摘要】：巖石是天然形成的材料,是賦存于自然界中非常復(fù)雜的介質(zhì)。它是由顆�；蚓w通過各種作用相互膠結(jié)在一起而形成的集合體,不同于一般的工程材料。由于巖石的形成過程比較特殊,使得在巖石的內(nèi)部構(gòu)造中存在著初始微裂紋和缺陷。然而,巖石所處的環(huán)境經(jīng)常與水溶液打交道,并且隨著國家各種工業(yè)的飛速發(fā)展,土壤環(huán)境中的水、地下水以及江河湖水等都受到不同程度的污染,使得水溶液呈現(xiàn)出不同的酸堿度,因此,水溶液會(huì)通過巖石初始微裂紋和缺陷侵蝕巖石,導(dǎo)致巖石的力學(xué)性質(zhì)受到影響,巖石的抗拉、抗壓強(qiáng)度及其斷裂韌度等力學(xué)參數(shù)都會(huì)受到其所處環(huán)境的影響。本文主要針對(duì)砂巖斷裂韌度化學(xué)損傷展開的相關(guān)試驗(yàn)研究,分別從宏觀上浸泡溶液PH值、試樣相對(duì)質(zhì)量和孔隙率的變化,以及試樣斷裂韌度隨時(shí)間和PH值的變化,研究砂巖斷裂韌度劣化機(jī)理。通過試驗(yàn)和對(duì)試驗(yàn)結(jié)果的分析,本文主要得到以下成果:①浸泡在水化學(xué)溶液中的砂巖,水-巖作用隨著時(shí)間的推移會(huì)發(fā)生不同的變化,同時(shí)其浸泡溶液PH值、試樣相對(duì)質(zhì)量以及孔隙率都會(huì)發(fā)生變化,并且三者的變化與水-巖作用的變化有著很好的相關(guān)性和一致性。②浸泡在水化學(xué)溶液中的砂巖,其斷裂韌度低于未浸泡的砂巖,表明砂巖斷裂韌度受到損傷,并且隨著浸泡時(shí)間的推移,其斷裂韌度越小;浸泡溶液PH值越小,其斷裂韌度越小。③比較未浸泡與浸泡后砂巖的破壞過程,可以發(fā)現(xiàn)它們的破壞過程有所不同,浸泡后砂巖破壞荷載更小,出現(xiàn)裂紋的時(shí)間更早,巖石壓密過程變長(zhǎng),破壞的時(shí)間變長(zhǎng),呈現(xiàn)出部分的延性,不同于初始狀態(tài)下的完全脆性破壞。④砂巖斷裂韌度存在明顯的尺寸效應(yīng),試樣尺寸越大,其值越大。⑤分析砂巖斷裂韌度的劣化規(guī)律,分別從時(shí)間和PH值兩個(gè)因素出發(fā),計(jì)算其損傷變量,發(fā)現(xiàn)其損傷有著明顯的規(guī)律性。
[Abstract]:Rock is a natural material and a very complex medium that exists in nature.It is a collection of particles or crystals cemented together by various interactions, which is different from general engineering materials.Because of the special formation process of rock, there are initial microcracks and defects in the internal structure of rock.However, the environment in which the rock is located often deals with aqueous solutions, and with the rapid development of various industries in the country, the water in the soil environment, groundwater and rivers and lakes are all polluted to varying degrees.The aqueous solution presents different pH values. Therefore, the aqueous solution will erode the rock through initial microcracks and defects, which will affect the mechanical properties of the rock and the tensile resistance of the rock.The mechanical parameters such as compressive strength and fracture toughness are affected by their environment.This paper mainly focuses on the related experimental research on chemical damage of sandstone fracture toughness. The PH value of solution, the change of sample relative mass and porosity, and the change of specimen fracture toughness with time and PH value, respectively, are studied in macroscopically.The degradation mechanism of sandstone fracture toughness is studied.Through the experiment and the analysis of the test results, this paper mainly obtains the following results: 1. The sandstone immersed in the hydrochemical solution has different changes in water-rock interaction over time, and the PH value of the soaking solution is also obtained.The relative mass and porosity of the samples will change, and there is a good correlation and consistency between the changes of them and the changes of water-rock interaction. The fracture toughness of sandstone immersed in hydrochemical solution is lower than that of unsoaked sandstone.The results show that the fracture toughness of sandstone is damaged, and the fracture toughness of sandstone decreases with the time of immersion, and the lower PH value of soaking solution, the smaller the fracture toughness of sandstone is. 3.It can be found that their failure process is different. After immersion, the failure load of sandstone is smaller, the cracking time is earlier, the compaction process of rock is longer, and the damage time is longer, showing partial ductility.Different from the fracture toughness of completely brittle failure sand under initial condition, there exists obvious size effect. The larger the specimen size, the greater the value of sand fracture toughness deterioration. The degradation law of sandstone fracture toughness is analyzed according to two factors, time and PH, respectively.By calculating the damage variables, it is found that the damage has obvious regularity.
【學(xué)位授予單位】：重慶大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU45

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本文編號(hào)：1722452