本文選題：核磁共振 + 橫向弛豫時(shí)間��； 參考：《湖北工業(yè)大學(xué)》2013年碩士論文

【摘要】：土是一種物理性質(zhì)非常復(fù)雜，而又與工程密不可分的地質(zhì)材料。眾所周知，土的物理力學(xué)性質(zhì)是通過其微觀結(jié)構(gòu)起作用，因此展開對(duì)土微觀結(jié)構(gòu)的研究，巖土力學(xué)行為便可以從本質(zhì)上得到解釋。但是，鑒于土種類的繁雜多樣化，其物理性質(zhì)也各不相同，所需研究的物理參數(shù)也極其復(fù)雜，并且目前的測(cè)定技術(shù)有限，結(jié)果往往不可靠，以至于至今對(duì)土的研究還沒有達(dá)到工程實(shí)用的要求；其次，由于軟黏土上述的各種復(fù)雜情況，使得研究者們?cè)趯?duì)土體微觀孔隙結(jié)構(gòu)的定量分析研究，揭示軟黏土的微觀孔隙分布及其變化規(guī)律等，非常困難。由于這些實(shí)際困難，在以往的研究中，研究者們大多從宏觀角度去研究土體的工程物理力學(xué)性質(zhì)，從表象上去解釋土的工程現(xiàn)象，但是這樣不能揭示出引起這種工程現(xiàn)象的內(nèi)在本質(zhì)機(jī)理。武漢地區(qū)地基土質(zhì)常常有著含水率高，壓縮性大，孔隙率高等特點(diǎn)。本文所研究土為武漢市漢街地區(qū)一建筑工地基底軟黏土，主要是由孔隙水，孔隙中氣體，黏土顆粒等物質(zhì)組成。本文通過大量的試驗(yàn)，定量化分析其孔隙孔徑分布特征，以及在干密度變化的過程中，孔徑分布的變化規(guī)律，為確定工程土體干密度對(duì)孔隙率、滲透性等的影響提供依據(jù)。 本文所進(jìn)行的主要研究工作以及獲得的結(jié)論如下： （1）介紹了對(duì)土體結(jié)構(gòu)性以及其微觀世界的研究現(xiàn)狀，指出以往所用試驗(yàn)方法所帶來的一些不準(zhǔn)確性，在本文中采用了更為先進(jìn)，試驗(yàn)結(jié)果更為可靠的研究方法——核磁共振，并將其與常規(guī)研究方法壓汞試驗(yàn)結(jié)果進(jìn)行對(duì)比。 （2）對(duì)所取試樣土進(jìn)行風(fēng)干重塑，制成七種不同干密度試樣，分別為：1.3g/cm3到1.705g/cm3之間，，并將試樣抽真空飽和。 （3）由核磁共振試驗(yàn)及CPMG反演軟件得出各試樣的核磁共振橫向弛豫時(shí)間的分布曲線圖，通過分析知橫向弛豫時(shí)間與孔徑成正比關(guān)系，換言之，該曲線圖就反映著試樣土的微觀孔隙分布，發(fā)現(xiàn)T2在1.5~1.7ms時(shí)，孔隙分布最多。 （4）由常規(guī)壓汞試驗(yàn)法測(cè)出其孔徑分布，得出干密度越大，試樣的主要孔隙分布區(qū)域孔徑越小，并由兩種試驗(yàn)進(jìn)行對(duì)比發(fā)現(xiàn)，干密度主要影響的是大孔隙的含量，對(duì)小孔隙含量改變不大；試驗(yàn)結(jié)果還表明該試樣土的孔隙主要是大孔隙，均占到80%以上。
[Abstract]:Soil is a kind of geological material which has very complex physical properties and is closely related to engineering.It is well known that the physical and mechanical properties of soil play an important role through its microstructure. Therefore, the mechanical behavior of rock and soil can be explained in essence by studying the microstructure of soil.However, in view of the diverse variety of soil types, their different physical properties, the extremely complex physical parameters to be studied, and the limited existing techniques for determination, the results are often unreliable,So far, the research on soil has not reached the practical requirements of engineering. Secondly, due to the various complex situations mentioned above, researchers are making quantitative analysis of the micro-pore structure of soil.It is very difficult to reveal the micro-pore distribution and its variation law of soft clay.As a result of these practical difficulties, in previous studies, researchers have mostly studied the engineering physical and mechanical properties of soil from a macro perspective, and interpreted the engineering phenomena of soil from a superficial perspective.But this does not reveal the intrinsic mechanism that causes this kind of engineering phenomenon.The foundation soil in Wuhan area is often characterized by high moisture content, high compressibility and high porosity.The soil studied in this paper is a soft clay on the basement of a construction site in Hanjie area of Wuhan City, which is mainly composed of pore water, gas in pores, clay particles and so on.Through a large number of experiments, the characteristics of pore pore size distribution and the variation law of pore size distribution in the course of dry density change are analyzed quantitatively, which provides the basis for determining the influence of dry density on porosity and permeability of engineering soil.The main research work and conclusions obtained in this paper are as follows:1) this paper introduces the present research situation of soil structure and its microcosm, and points out some inaccuracies brought about by the test methods used in the past. In this paper, a more advanced and more reliable research method, nuclear magnetic resonance (NMR), is adopted.The results of mercury injection test were compared with those of conventional research methods.2) the sample soil was remolded by air drying, and seven kinds of samples with different dry densities were made, which ranged from: 1.3 g / cm ~ 3 to 1.705g/cm3, and the samples were saturated by vacuum.(3) the distribution curves of transverse relaxation time of nuclear magnetic resonance (NMR) were obtained from NMR test and CPMG inversion software. The relationship between transverse relaxation time and pore size was found to be in direct proportion by analysis, in other words,The curve reflects the micropore distribution of the sample soil, and it is found that when T2 is in 1.5~1.7ms, the pore distribution is the most.(4) the pore size distribution of the sample is measured by conventional mercury injection test. The larger the dry density is, the smaller the pore size is in the main pore distribution area of the sample. By comparing the two tests, it is found that the dry density mainly affects the content of macropores.The test results also show that the porosity of the soil is mainly macroporous, accounting for more than 80%.
【學(xué)位授予單位】：湖北工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：TU41

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 房后國(guó),劉娉慧,肖樹芳,林德全;海積軟土排水固結(jié)機(jī)理分析[J];吉林大學(xué)學(xué)報(bào)(地球科學(xué)版);2005年02期

2 王清,王鳳艷,肖樹芳;土微觀結(jié)構(gòu)特征的定量研究及其在工程中的應(yīng)用[J];成都理工學(xué)院學(xué)報(bào);2001年02期

3 洪振舜,劉漢龍,NEGAMI Takehito;Remolded Undrained Strength of Soils[J];China Ocean Engineering;2003年01期

4 董邑寧,徐日慶,龔曉南;蕭山粘土的結(jié)構(gòu)性對(duì)滲透性質(zhì)影響的試驗(yàn)研究[J];大壩觀測(cè)與土工測(cè)試;2000年06期

5 吳義祥;工程粘性土微觀結(jié)構(gòu)的定量評(píng)價(jià)[J];中國(guó)地質(zhì)科學(xué)院院報(bào);1991年02期

6 吳義祥;張宗祜;凌澤民;;土體微觀結(jié)構(gòu)的研究現(xiàn)況評(píng)述[J];地質(zhì)論評(píng);1992年03期

7 施斌;粘性土微觀結(jié)構(gòu)研究回顧與展望[J];工程地質(zhì)學(xué)報(bào);1996年01期

8 朱海之;高鳳英;裴靜嫻;;黃土顆粒成分在顯微鏡下的分析[J];地質(zhì)科學(xué);1959年03期

9 王幼麟;;粘土礦物“疊片體”與粘性土的工程性質(zhì)[J];地質(zhì)論評(píng);1985年04期

10 張宗祜;中國(guó)黃土高原中幾個(gè)剖面的巖性、地層分析[J];海洋地質(zhì)與第四紀(jì)地質(zhì);1983年03期

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