ou边坡条稳定与挡土墙.doc
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1、2016 learning implement to tube main leaders topic seminar spirit counselling material 2016 learning implement to tube main leaders topic seminar spirit counselling material March 7, XI General Secretary to I province delegation participate in considered and published has important speech, on XXX pr
2、ovince people for China revolution victory and Socialist construction made of contribution give has certainly, on I province past five years implementation focus strategy, and grasp focus industry, economic social development made of results give has certainly, Clarified the demands for development
3、of XXX, referring to both directions, tasks and issues, teaching methods, for the current and future development in Heilongjiang province, is of great practical significance and far-reaching historical significance. March 22 to 24th, provincial held has province tube main leaders topic seminar, prov
4、incial Secretary Wang Xiankui comrade in seminar opening province do has important speech, Wang Xiankui stressed: in-depth learning acquisition General Secretary of speech, is on XXX a political account, we must put learning implement XI General Secretary important speech spirit as major political t
5、ask, adapted and led economic development new normal, insisted to economic construction for Center not shake, implement implementation new development concept, weaknesses, and swagger grams short, and yangchangbuduan, Stimulate the endogenous dynamics, formation effect of EMU, firm implementation of
6、 the five planning, the development of key industries, open Dragon River comprehensive revitalization new journey, struggling to get out of a high quality, efficient, better structure and development road of revitalization of the advantages into full play. March 29 to 30th, the Committee organized a
7、 pipe major thematic seminar of leading cadres prefectural comrade Jia Yumei made an important speech at the opening ceremony. Jia Shuji stressed, full district upper and lower must to effective enhanced learning publicity implement implementation XI General Secretary important speech spirit of poli
8、tical consciously, and thought consciously, and action consciously and mission consciously, put learning XI General Secretary and provincial Secretary Wang Xiankui speech spirit as current primary political task, to more strongly of attitude, and more powerful of measures, and more full of drive pro
9、moted forest transformation development, struggled to out of forest transformation development new, ensure as scheduled achieved full built forest society of target. Today the County for convening this Conference, is to fully implement the arrangements of the provincial, prefectural, and is a major
10、political task. County-wide each of the party members and cadres must earnestly study, deeply understand, enter into the heart, done outside the heart, of the line armed with Jia, Secretary of spirit and mind, practice, work, below, I XX practical study Jia Shujis important speech spirit with you. A
11、wareness, deepen the County, General Secretary第六章 边坡稳定与挡土墙第一节 边坡稳定一、概述 引发边坡滑动的原因:坡顶堆放材料或建造建筑物、构筑物;车辆行驶、地震等引起的振动;土体中含水量或孔隙水压力增加;雨水或地面水流入边坡竖向裂缝等。二、边坡稳定地基稳定性可采用圆弧滑动面法进行验算.最危险的滑动面上诸力对滑动中心所产生的抗滑力矩与滑动力矩应符合下式要求: MR/MS1.2 式中MS-滑动力矩;MR-抗滑力矩.当边坡坡角大于45,坡高大于8m时,尚应按式MR/MS1.2验算坡体稳定性.在建设场区内,由于施工或其他因素的影响有可能形成滑坡的地段,
12、必须采取可靠的预防措施,防止产生滑坡。对具有发展趋势并威胁建筑物安全使用的滑坡,应及早整治,防止滑坡继续发展。必须根据工程地质、水文地质条件以及施工影响等因素,认真分析滑坡可能发生或发展的主要原因,可采取下列防治滑坡的处理措施:1.排水:应设置排水沟以防止地面水浸入滑坡地段,必要时尚应采取防渗措施。在地下水影响较大的情况下,应根据地质条件,做好地下排水工程;2.支挡:根据滑坡推力的大小、方向及作用点,可选用重力式抗滑挡墙、阻滑桩及其他抗滑结构。抗滑挡墙的基底及阻滑桩的桩端应埋置于滑动面以下的稳定土(岩)层中。必要时,应验算墙顶以上的土(岩)体从墙顶滑出的可能性;3.卸载:在保证卸载区上方及两侧
13、岩土稳定的情况下,可在滑体主动区卸载,但不得在滑体被动区卸载;4.反压:在滑体的阻滑区段增加竖向荷载以提高滑体的阻滑安全系数。三、滑坡推力应按下列规定进行计算: 1.当滑体具有多层滑动面(带)时,应取推力最大的滑动面(带)确定滑坡推力;2.选择平行于滑动方向的几个具有代表性的断面(一般不得少于2个,其中应有一个是滑动主轴断面)进行计算。根据不同断面的推力设计相应的抗滑结构;3.当滑动面为折线形时,滑坡推力可按下式计算(图6.4.3)。Fn=Fn-1+tGnt-Gnntann-cnln (6.4.3-1)=cos(n-1-n)-sin(n-1-n)tann (6.4.3-2)式中Fn,Fn-1-
14、第n块、第n-1块滑体的剩余下滑力;-传递系数;t-滑坡推力安全系数;Gnt,Gnn-第n块滑体自重沿滑动面、垂直滑动面的分力;n-第n块滑体沿滑动面土的内摩擦角标准值;cn-第n块滑体沿滑动面土的粘聚力标准值;ln-第n块滑体沿滑动面的长度;4.滑坡推力作用点,可取在滑体厚度的二分之一处;5.滑坡推力安全系数,应根据滑坡现状及其对工程的影响等因素确定,对地基基础设计为甲级的建筑物宜取1.25,设计等级为已级的建筑物宜取1.15,设计等级为丙级的建筑物宜取1.05;6.根据土(岩)的性质和当地经验,可采用试验和滑坡反算相结合的方法,合理地确定滑动面上的抗剪强度。四、边坡开挖应按表6-2规定确定
15、放坡坡度。五、坡顶上的建筑位置位于稳定土坡坡顶上的建筑,当垂直于坡顶边缘线的基础底面边长小于或等于3m时,其基础底面外缘线至坡顶的水平距离(图5.4.2)应符合下式要求,但不得小于2.5m:条形基础a3.5b-d/tan矩形基础a2.5b-d/tan式中a-基础底面外边缘线至坡顶的水平距离;b-垂直于坡顶边缘线的基础底面边长;d-基础埋置深度;-边坡坡角.当基础底面外边缘线至坡顶的水平距离不满足式(5.4.2-1),(5.4.2-2)的要求时,可根据基底平均压力按公式(5.4.1)确定基础距边顶边缘的距离和基础埋深.第二节 挡土墙的土压力一、概念:1、挡土墙:为支挡土体,保证其稳定而修筑的建筑
16、物2、土压力:指墙后填土由于它的自重或作用在填土表面上的荷载对墙背所产生的侧向压力二、挡土墙的位移与土体状态据挡土墙位移方向,填土所处状态,土压力可分为:1、静止土压力:(earth pressure at rest)挡土墙与填土保持相对静止状态强度:P0 KPa 土压力:E0 KN/m2、主动土压力:(active earth pressure)挡土墙在墙后土体的作用下,向前移动或转动,填土应力状态处于极限平衡状态,土压力减小到最小值强度: Pa KPa 土压力:Ea KN/m3、被动土压力:(passive earth pressure)当挡土墙由于外部荷载作用,产生向填土方向的位移,填土
17、达到极限平衡状态土压力增大到最大值强度: Pp KPa 土压力:Ep KN/m三、静止土压力计算1、压强 分布:均质土层三角形分布填土中有地下水存在浮重度成层土荷载作用2、土压力E0大小:E0 =(三角锥体体积)=三角面积=1/2h2K0方向:水平 指向墙背作用点:通过压力图形的行心离墙底H/3 m 处。第三节 库仑土压力理论一、基本理论:1、墙后填土为无粘性土2、破坏面为通过墙踵的平面3、滑动土楔为刚体二、库仑主动土压力其中: :墙背倾角:墙后填土表面与水平面夹角:外摩擦角:内摩擦角特例:若:=0 =0 =0 时朗肯土压力库仑主动土压力 大小:方向:在墙背法线上方,与法线成角,与水平面夹角+
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