發(fā)布時(shí)間：2018-06-15 18:18

  本文選題：表觀m值 + 本底m值�。� 參考：《成都理工大學(xué)》2017年碩士論文

【摘要】：長(zhǎng)期遭受水平作用力的樁基礎(chǔ),其水平載荷能力是直接影響樁基安全穩(wěn)定的關(guān)鍵性因素。水平受荷樁的承載能力主要受樁身性質(zhì)與地基土體性質(zhì)控制,其中地基土的水平抗力系數(shù)的比例系數(shù)m值是關(guān)系到樁-土相互作用的地基土的物理參數(shù),是衡量地基土體水平抗力大小的物理量,也是計(jì)算樁基水平承載力的參數(shù)值。地基土體性質(zhì)是影響m值的主要因素,不同土性、不同設(shè)計(jì)要求m值取值不盡相同;對(duì)于甲級(jí)設(shè)計(jì)要求建筑樁基需要通過現(xiàn)場(chǎng)單樁水平靜載試驗(yàn)獲取m值,而大部分一般建筑樁基則通過規(guī)范經(jīng)驗(yàn)取值與工程類比綜合確定,因此m值的取值是否合理直接關(guān)系到水平受荷樁的承載力設(shè)計(jì)是否恰當(dāng)。本文基于西南山區(qū)輸電線塔基出現(xiàn)最多的碎石土地基開展m值取值研究;而碎石土分類廣,性質(zhì)差異性大,規(guī)范取值范圍大,綜合選取隨意性大;經(jīng)文獻(xiàn)查閱后發(fā)現(xiàn)密實(shí)度與含石量是影響碎石土性質(zhì)的主要兩個(gè)因素,其不同性狀碎石土地基樁-土相互作用下表觀m值取值差異大,不同性狀碎石土地基能夠發(fā)揮的極限水平抗力大小也欠缺研究。因此本文采用室內(nèi)物理模擬試驗(yàn)方法,針對(duì)不同性狀碎石土地基進(jìn)行表觀m值與本底m值取值探討,設(shè)計(jì)并開展了改變碎石土地基密實(shí)度、含石量及樁寬的單樁水平靜載荷模型試驗(yàn)與水平壓縮試驗(yàn),主要得到以下結(jié)論與認(rèn)識(shí):(1)單樁水平靜載荷試驗(yàn)得到的表觀m值是由地基土體性質(zhì)控制的地基系數(shù)。密實(shí)度的變化對(duì)m值的影響最顯著,其次是含石量,而樁寬的變化幾乎對(duì)表觀m值幾乎不影響。碎石土密實(shí)度Dr每增加20% ,表觀m值提高1.83倍,在Dr=60.0%的碎石土地基表觀m值為175.61MN/m~4。含石量P5每增加10% ,表觀m值提高1.24倍。(2)樁基在水平力作用下的臨界荷載Hcr與極限荷載Hu隨密實(shí)度Dr、含石量P5及樁寬的增加而增大。最松散的土體性質(zhì)最差,樁頂容許位移最小。密實(shí)度及含石量較高的土體在高水平荷載作用下土體的變形主要由粗顆粒之間的錯(cuò)動(dòng)產(chǎn)生。含石量高的碎石土偏于硬化,可以有效提高土體水平承載能力。(3)m值是由地基土體性質(zhì)直接影響的土體本底物理量參數(shù),反應(yīng)地基土體水平抗力與水平應(yīng)變的關(guān)系規(guī)律,密實(shí)度對(duì)碎石土本底m值的影響最為顯著,隨密實(shí)度的增大m值會(huì)明顯增大。工程結(jié)構(gòu)的作用使得土體不能完全發(fā)揮其水平抗力性能,從而使得出m值偏小,在無樁身作用下進(jìn)行水平壓縮可以獲得最大的本底m值。比較兩種試驗(yàn)獲得的m值,水平壓縮載荷試驗(yàn)獲取的本底m值比表觀m值要大,更能反應(yīng)碎石土的水平抗力性能;一般本底m值比表觀m值大1.37倍,相比相同樁寬、相同密實(shí)度碎石土地基,不同加載方式得到的m值也有較大差別,樁身擠壓土體量越多m值越大。(4)碎石土地基水平受荷單樁泥面位移x與表觀m值呈現(xiàn)為非線性的冪指數(shù)關(guān)系,關(guān)系式為m=b_m(x/B×10~3)~(-1.038),bm取值參考表5-5 ,碎石土地基冪指數(shù)平均k值為-1.038。(5)利用綜合剛度原理提出的雙參數(shù)法分析各密實(shí)度單樁靜載模型試驗(yàn)數(shù)據(jù)進(jìn)行計(jì)算分析,土抗力系數(shù)K隨深度非線性變化,K=mz0.7。對(duì)于碎石土地基在1/n=0.7時(shí)計(jì)算得到的各內(nèi)力最貼切實(shí)測(cè)數(shù)據(jù)樁土綜合剛度比樁身剛度要小,在碎石土地基中樁土之間是負(fù)附著形式作用,樁的一部分是作為土體。
[Abstract]:The horizontal load capacity is the key factor affecting the safety and stability of pile foundation for a long time. The bearing capacity of the pile is mainly controlled by the character of the pile body and the soil properties of the foundation, and the ratio coefficient m of the horizontal resistance coefficient of the foundation soil is the physics of the foundation soil which is related to the pile soil interaction. Parameter is the physical quantity to measure the horizontal resistance of foundation soil, and it is also the parameter value of calculating the horizontal bearing capacity of the pile foundation. The soil property of the foundation is the main factor affecting the m value. The different soil properties and the different design requirements of the m value are not the same; for the first grade design, the building pile foundation needs to obtain the m value through the static load test of the single pile. Most general building piles are determined by the standard experience value and engineering analogy, so whether the value of m value is reasonable directly relates to the proper design of the bearing capacity of the horizontal bearing pile. This paper is based on the study of the value of the m value based on the most lithotripsy ground base of the transmission line tower base in the southwest mountain area; and the classification of the gravel soil is wide and the nature is poor. It is large in heterosexual, large range of standard values and comprehensive selection of randomness. After consulting the literature, it is found that density and stone content are the two main factors affecting the properties of gravel soil. The apparent m values of different properties of gravel soil under the interaction of soil foundation pile soil interaction are very different. Therefore, in this paper, the indoor physical simulation test method is used to study the apparent m values and the values of the base m values for different properties of the gravel soil foundation. A single pile horizontal static load model test and horizontal compression test are designed and carried out to change the soil base density, stone content and pile width. The main conclusions are as follows: (1) single The apparent m value obtained by the static load test of the pile is the foundation coefficient controlled by the soil properties of the foundation. The change of the density has the most significant influence on the m value, followed by the stone content, and the change of the pile width almost has no effect on the apparent m value. The gravel soil density Dr increases 20%, the apparent m value increases 1.83 times, and the apparent m in the gravel soil base of Dr=60.0% is m. The value of the 175.61MN/m~4. stone content P5 increases 10% and the apparent m value increases 1.24 times. (2) the critical load of the pile foundation under horizontal force and the limit load Hu increases with the density Dr, the rock content P5 and the pile width. The most loose soil property is the worst, the allowable displacement of the pile top is minimum. The soil with high density and high stone content is in the high horizontal load. The deformation of the soil is mainly caused by the dislocation between the coarse particles. The gravel soil with high stone content is partial to hardening and can effectively improve the horizontal bearing capacity of the soil. (3) the m value is the physical parameter of the soil base, which is directly affected by the soil properties of the foundation, and the relationship between the horizontal and horizontal strain of the soil soil, and the compactness to the gravel. The effect of the m value on the soil base is the most significant, with the increase of the compactness, the m value will increase obviously. The effect of the engineering structure makes the soil not fully play its horizontal resistance performance, so that the m value is smaller and the maximum bottom m value can be obtained under the horizontal compression without the pile body. Compared with the m value obtained from the two tests, the horizontal compression load test is compared. The base m value obtained is larger than the apparent m value, and it can reflect the horizontal resistance performance of the gravel soil more than the apparent m value. The general background m value is 1.37 times larger than the apparent m value. Compared with the same pile width, the same compactness gravel land base, the m value of the different loading ways also has greater difference, the greater the m value of the pile body extrusion soil. (4) the gravel soil base level is loaded single pile. The surface displacement X and the apparent m value are nonlinear power exponent relation, the relation is m=b_m (x/B x 10~3) ~ (-1.038), BM value reference table 5-5, the average K value of the lithotripsy soil foundation power exponent is -1.038. (5) using the double parameter method proposed by the comprehensive stiffness principle to analyze the static load model test data of each compactness single pile, and the soil resistance coefficient K. With the nonlinear variation of depth, the most accurate measured data of the internal forces obtained by K=mz0.7. for the gravel soil base at 1/n=0.7 are smaller than the pile stiffness. The pile and soil are negative in the gravel soil foundation, and a part of the pile is used as the soil.
【學(xué)位授予單位】：成都理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TU473.1

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 劉斌;趙其華;丁梓涵;喻豪俊;;斜坡加固碎石土樁基水平承載力影響研究[J];科學(xué)技術(shù)與工程;2017年02期

2 帥正陽;趙其華;丁梓涵;喻豪俊;;碎石土斜坡場(chǎng)地樁基m值影響因素分析[J];科學(xué)技術(shù)與工程;2016年29期

3 穆紅海;彭社琴;趙其華;喻豪俊;丁梓涵;吳浩;;碎石土斜坡樁基水平承載特性模型試驗(yàn)[J];科學(xué)技術(shù)與工程;2016年24期

4 戴自航;王云鳳;盧才金;;水平荷載單樁計(jì)算的綜合剛度和雙參數(shù)法桿系有限元數(shù)值解[J];巖石力學(xué)與工程學(xué)報(bào);2016年10期

5 李曉明;趙慶斌;楊祈敏;趙其華;陳繼彬;喻豪俊;;碎石土-基巖斜坡樁基參數(shù)m值影響因素研究[J];電力勘測(cè)設(shè)計(jì);2016年03期

6 丁梓涵;趙其華;彭社琴;喻豪俊;;地基土強(qiáng)度對(duì)樁土水平作用特性及m值影響的模型試驗(yàn)研究[J];水文地質(zhì)工程地質(zhì);2016年03期

7 歐陽芳;張建經(jīng);韓建偉;王志佳;吳金標(biāo);楊義奎;;包裹碎石樁和碎石樁復(fù)合地基抗震性能對(duì)比試驗(yàn)研究[J];巖土力學(xué);2016年04期

8 王春得;沈秋武;吳銳;付敏;楊呈剛;;含石量對(duì)碎石土工程特性的影響試驗(yàn)研究[J];鐵道建筑;2016年02期

9 賀小衛(wèi);宋得亞;袁浩允;;基于m法的凍土樁基受力性能研究[J];市政技術(shù);2016年01期

10 董輝;胡自然;傅鶴林;陳鋮;陳璽文;;質(zhì)量密度及圍壓影響的堆積碎石土變形特性分析[J];中南大學(xué)學(xué)報(bào)(自然科學(xué)版);2015年10期

相關(guān)碩士學(xué)位論文 前6條

1 喻豪俊;斜坡碎石土地基單樁水平承載特性研究[D];成都理工大學(xué);2016年

2 丁梓涵;西南山區(qū)斜坡場(chǎng)地碎石土地基水平抗力系數(shù)的比例系數(shù)m值取值研究[D];成都理工大學(xué);2016年

3 吳浩;碎石土~基巖復(fù)合基樁水平作用力參數(shù)m值研究[D];成都理工大學(xué);2015年

4 肖鵬;軟土地基樁基礎(chǔ)水平承載性能研究[D];廣州大學(xué);2013年

5 張小輝;層狀黃土地基水平受荷樁承載性狀研究[D];西安建筑科技大學(xué);2013年

6 劉俊生;基于水平荷載和傾斜荷載的樁基m法研究[D];天津大學(xué);2009年

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本文編號(hào)：2023048