本文選題：膨脹土 + 動(dòng)剪切模量�。� 參考：《華北水利水電大學(xué)》2016年碩士論文

【摘要】：膨脹土是一種特殊的黏性土,其黏粒成分主要為強(qiáng)親水性礦物蒙脫石,具有多裂隙性、超固結(jié)性、吸水膨脹軟化、失水干縮開(kāi)裂,且反復(fù)變形的特性。盡管膨脹土的巖土工程災(zāi)害和工程地質(zhì)災(zāi)害已經(jīng)被人們所了解,但對(duì)其在動(dòng)荷載作用下將會(huì)表現(xiàn)出的致災(zāi)性和易損性還缺少全面和深入的了解。膨脹土因其顯著的脹縮性表現(xiàn)出非常差的工程特性,所以不難想象膨脹土在動(dòng)荷載的作用下勢(shì)必很容易引起土體瞬間失穩(wěn)或土體疲勞破壞等異常的變形甚至產(chǎn)生工程病害,對(duì)地下工程及地表結(jié)構(gòu)產(chǎn)生損害,以致導(dǎo)致財(cái)產(chǎn)損失甚至對(duì)人民生命安全產(chǎn)生威脅。所以對(duì)膨脹土進(jìn)行動(dòng)力學(xué)研究是極其必要的,這有著非常重要的科學(xué)意義和實(shí)用價(jià)值。本文用GDS共振柱系統(tǒng),對(duì)不同自由膨脹率、含水率、干密度和圍壓下膨脹土的動(dòng)剪切模量和阻尼比進(jìn)行研究,并取得了一些結(jié)論。(1)原土與加入不同比例的膨潤(rùn)土進(jìn)行對(duì)比試驗(yàn)后發(fā)現(xiàn),在小應(yīng)變條件下,自由膨脹率越大,試樣的動(dòng)剪模量也越大。自由膨脹率為110%的試樣的動(dòng)剪切模量明顯高于自由膨脹率分別為85%和60%試樣的動(dòng)剪切模量。試樣的動(dòng)剪切模量隨著自由膨脹率的增大而增大,且增大的幅度明顯增加。但是當(dāng)動(dòng)剪應(yīng)變?cè)龃蟮揭欢ㄖ禃r(shí),這種增加的幅度變小了。而且自由膨脹率越大,試樣的阻尼比就越大。自由膨脹率為110%的試樣的阻尼比高于自由膨脹率分別為85%和60%試樣的阻尼比。(2)在應(yīng)變條件為10-4-10-2下,當(dāng)試樣含水率為20%、23%、26%時(shí),隨著含水率的增大,試樣動(dòng)剪切模量不斷減小,而且減小幅度明顯增加。同時(shí)試樣含水率越大,阻尼比越小。含水率為26%的試樣的阻尼比明顯小于含水率為23%和20%試樣的阻尼比。隨著含水率的增大,試樣阻尼比減小,而且減小的趨勢(shì)上升。隨著含水率的增大,含水率對(duì)膨脹土阻尼比的影響是逐漸增強(qiáng)的。(3)當(dāng)應(yīng)變?yōu)樾?yīng)變時(shí),在試樣的干密度為1.45 g/cm3、1.57 g/cm3、1.69 g/cm3的條件下,干密度增大時(shí),試樣的動(dòng)剪切模量也隨之增大,而且增大的趨勢(shì)基本相同。當(dāng)試樣干密度增大時(shí),阻尼比也隨之增大。隨著干密度的增大,試樣的阻尼比也隨之增大,而且增大的趨勢(shì)基本相同。(4)在小應(yīng)變下,固結(jié)圍壓為50 kPa、100 kPa、200 kPa,隨著圍壓的增大,試樣的動(dòng)剪切模量也隨之增大,而且增大的趨勢(shì)呈上升狀態(tài)。但是當(dāng)動(dòng)剪應(yīng)變?cè)龃蟮揭欢ㄖ禃r(shí),這種趨勢(shì)又減弱了。當(dāng)圍壓增大時(shí),試樣阻尼比也隨之增大。(5)用雙曲線模型對(duì)1/G與γ進(jìn)行擬合,把結(jié)果整理分析后看出,不同自由膨脹率、含水率、干密度和圍壓下,1/G與γ均成良好的直線關(guān)系。試驗(yàn)點(diǎn)與直線有較好的擬合性,離散程度較小。說(shuō)明雙曲線模型能夠很好地描述不同自由膨脹率、含水率、干密度和圍壓下膨脹土的動(dòng)應(yīng)力應(yīng)變關(guān)系。
[Abstract]:Expansive soil is a kind of special clay. Its clay is mainly composed of strong hydrophilic mineral montmorillonite. It has the characteristics of multiple fissures, overconsolidation, swelling and softening of water absorption, dry shrinkage and cracking of lost water, and repeated deformation. Although the geotechnical engineering disasters and engineering geological disasters of expansive soil have been well known, there is still a lack of comprehensive and in-depth understanding of the disaster-causing and vulnerability of expansive soils under dynamic loads. Because of its remarkable dilatancy and shrinkage, expansive soil shows very poor engineering characteristics, so it is not difficult to imagine that expansive soil under the action of dynamic load will easily lead to transient instability of soil or abnormal deformation of soil such as fatigue failure of soil, and even produce engineering diseases. Damage to underground works and surface structures, resulting in property losses and even a threat to the safety of people. Therefore, it is extremely necessary to study the dynamics of expansive soil, which has very important scientific significance and practical value. In this paper, the dynamic shear modulus and damping ratio of expansive soil under different free expansion ratio, moisture content, dry density and confining pressure are studied by GDS resonance column system. Some conclusions have been obtained. (1) comparing the original soil with the bentonite with different proportion, it is found that under the condition of small strain, the larger the free expansion ratio is, the greater the dynamic shear modulus of the sample is. The dynamic shear modulus of the specimen with free expansion rate of 110% is significantly higher than that of the specimen with free expansion rate of 85% and 60%, respectively. The dynamic shear modulus of the specimen increases with the increase of the free expansion rate, and the amplitude of the increase is obviously increased. But when the dynamic shear strain increases to a certain value, the amplitude of this increase becomes smaller. Moreover, the larger the free expansion rate, the greater the damping ratio of the sample. The damping ratio of the specimen with 110% free expansion ratio is higher than that of the sample with free expansion rate of 85% and 60%, respectively. When the strain condition is 10-4-10-2, when the moisture content of the sample is 20% and 26cm, the dynamic shear modulus of the specimen decreases with the increase of the moisture content. And the decrease is obviously increased. At the same time, the higher the moisture content of the sample, the smaller the damping ratio. The damping ratio of the sample with water content of 26% is obviously lower than that of the sample with moisture content of 23% and 20%. With the increase of moisture content, the damping ratio of the sample decreases and the decreasing trend increases. With the increase of moisture content, the effect of moisture content on the damping ratio of expansive soil is gradually enhanced. When the strain is small, the dynamic shear modulus of the specimen increases when the dry density of the sample is 1.45 g / cm ~ (3) ~ (-1) g / cm ~ (3) and 1.57 g / cm ~ (3) C ~ (3 +) 1.69 g/cm3. And the trend of increase is basically the same. When the dry density of the sample increases, the damping ratio also increases. With the increase of dry density, the damping ratio of the sample increases, and the increasing trend is basically the same. 4) under small strain, the consolidation confining pressure is 50kPa100kPa100kPa200kPa. with the increase of confining pressure, the dynamic shear modulus of the sample increases. And the increasing trend is on the rise. But when the dynamic shear strain increases to a certain value, this trend weakens again. When the confining pressure increases, the damping ratio of the sample also increases. 5) the hyperbolic model is used to fit 1 / G and 緯. The results show that the free expansion ratio, moisture content, dry density and confining pressure of 1 / G and 緯 are all in good linear relationship. The test points fit well with the straight line, and the dispersion degree is small. The hyperbolic model can well describe the dynamic stress-strain relationship of expansive soil under different free expansion ratio, water content, dry density and confining pressure.
【學(xué)位授予單位】：華北水利水電大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TU443

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 黃志全;李磊;賈景超;岳康興;孫怡;;非飽和黃土動(dòng)剪切模量和阻尼比共振柱試驗(yàn)研究[J];人民長(zhǎng)江;2015年05期

2 胡曉軍;吳延枝;;膨脹土改良技術(shù)研究綜述[J];合肥學(xué)院學(xué)報(bào)(自然科學(xué)版);2014年04期

3 賈景超;劉娉慧;黃志全;;膨脹土動(dòng)剪切模量和阻尼比影響因素試驗(yàn)研究[J];人民黃河;2014年09期

4 孫田;陳國(guó)興;周恩全;李小軍;;瓊州海峽100m以淺海洋土動(dòng)剪切模量比和阻尼比試驗(yàn)研究[J];巖土工程學(xué)報(bào);2013年S2期

5 孫田;陳國(guó)興;周恩全;李小軍;;深層海床粉質(zhì)黏土動(dòng)剪切模量和阻尼比試驗(yàn)研究[J];土木工程學(xué)報(bào);2012年S1期

6 王志杰;駱亞生;王瑞瑞;楊利國(guó);譚東岳;;不同地區(qū)原狀黃土動(dòng)剪切模量與阻尼比試驗(yàn)研究[J];巖土工程學(xué)報(bào);2010年09期

7 黃志全;吳林峰;王安明;姜彤;;基于原位剪切試驗(yàn)的膨脹土邊坡穩(wěn)定性研究[J];巖土力學(xué);2008年07期

8 齊劍峰;欒茂田;楊慶;馬太雷;袁穎;;飽和黏土動(dòng)剪切模量與阻尼比的試驗(yàn)研究[J];巖土工程學(xué)報(bào);2008年04期

9 王炳輝;陳國(guó)興;王晶華;;寧波近海沉積土動(dòng)力特性的試驗(yàn)研究[J];自然災(zāi)害學(xué)報(bào);2007年04期

10 謝定義;;中國(guó)土動(dòng)力學(xué)的發(fā)展現(xiàn)狀與存在的問(wèn)題[J];西北地震學(xué)報(bào);2007年01期

相關(guān)博士學(xué)位論文 前1條

1 孫靜;巖土動(dòng)剪切模量阻尼試驗(yàn)及應(yīng)用研究[D];中國(guó)地震局工程力學(xué)研究所;2004年

相關(guān)碩士學(xué)位論文 前8條

1 李登超;舟山漁場(chǎng)原位海洋土靜動(dòng)力特性研究[D];浙江海洋學(xué)院;2015年

2 王飛;膨脹土動(dòng)力特性的試驗(yàn)研究[D];西北農(nóng)林科技大學(xué);2014年

3 朱立華;邯鄲新近沉積粉土動(dòng)力特性研究[D];河北工程大學(xué);2013年

4 王佳;粗粒土動(dòng)彈性模量與阻尼比試驗(yàn)研究[D];中南大學(xué);2013年

5 陳光仔;時(shí)間效應(yīng)對(duì)土體小應(yīng)變動(dòng)力特性影響及其細(xì)觀機(jī)理研究[D];浙江大學(xué);2013年

6 周小生;雙向循環(huán)荷載作用下膨脹土的動(dòng)力特性與路基響應(yīng)特征研究[D];中國(guó)科學(xué)院研究生院（武漢巖土力學(xué)研究所）;2010年

7 彭海燕;水泥土和灰土動(dòng)力特性的試驗(yàn)研究[D];太原理工大學(xué);2009年

8 陳偉;原狀膨脹土非飽和強(qiáng)度特征與動(dòng)力性能試驗(yàn)研究[D];中國(guó)科學(xué)院研究生院（武漢巖土力學(xué)研究所）;2007年

，

本文編號(hào)：1821083