电大桥梁墩台基础期末复习考试题库资料小抄汇总.doc

电大《桥梁墩台基础》期末考试题库资料小抄汇总
1.简支梁桥的墩台沉降和位移的容许极限值,不宜超过下列规定( 墩台均匀总沉降值2.0L 、相邻墩台均匀总沉降差值1.0L、墩台顶面水平位移值0.5L)
2.单柱式桥墩,适用于(水流与桥轴斜交角大于15度的桥梁、 河流急弯,流向不固定的桥梁 )
3.框架式桥台是一种配用桩基础的轻型桥台适用于(地基承载力低、台身高大于4M、跨径大于10M)的桥梁(多选)
4.粘性土地基的含水状态和软硬程度以液性指数I表示,当I为( 0≤I＜0.5 )表示为硬塑状态(多选)
5.按经济合理和施工可能的原则,通常在下列情况下,可考虑采用沉井基础(A.上部荷载大,结构对基础的变位敏感,浅层地基土的承载力不足,在一定深度下有合适的持力层时、B.在山区河流中,浅层地基土虽然较好,但冲刷大,或河中有较大卵石不便桩基础施工时、C.岩石表面较平坦且覆盖层较薄,但河水较深 ) (多选)
1.对一般工程,当其所在地区的基本烈度为7度时,均应考虑抗震设防( √ )
2.单柱式桥墩具有施工便利,速度快,圬工体积小,工程造价低和比较美观等优点( × )
3.钢筋混凝土柔性排架桩墩台,由成排的预制钢筋混凝土沉入桩或钻孔灌注桩顶端连以钢筋混凝土盖梁组成( √)
4.土的粘性指数Ip<1的为粘性土( X )
5.朗金土压力理论一般情况适用条件为:挡土墙墙背垂直,墙后填土表面水平,挡土墙墙背光滑( √ )
1.对一般工程,当其所在地区的基本烈度为7度时,均应考虑抗震设防(√)
2.单柱式桥墩具有施工便利,速度快,圬工体积小,工程造价低和比较美观等优点(×)
3.钢筋混凝土柔性排架桩墩台,由成排的预制钢筋混凝土沉入桩或钻孔灌注桩顶端连以钢筋混凝土盖梁组成( √ )
4.土的粘性指数Ip<1的为粘性土( ×)
5.朗金土压力理论一般情况适用条件为:挡土墙墙背垂直,墙后填土表面水平,挡土墙墙背光滑( √ )
二、简答题(每题10分，共50分)
1.简述柱式桥墩的型式及适用条件?单柱式桥墩适用于水流与桥轴斜交角大于15度的桥梁或河流急弯,流向不固定的桥梁 双柱式适用于水流与桥轴斜交角小于15度,仅有较小的漂流物或轻微的流水河流中哑铃式适用于有较多漂流物或较严重的流水河流上混合双柱式适用于有较严重的漂流物或流水的河流上,当墩身较高时.
2.选择地基处理方法时，需考虑哪些因素？1.地基条件 2.建筑物结构条件 3.施工条件
3.确定基础埋置深度应考虑的因素？1.地基的地质条件 2.河流冲刷深度3.冻结深度4.上部结构的型式 5.地形条件
4.刚性基础的特点是什么？稳定性好,施工简便,能承受较大的荷载,缺点是自重大,扩大基础面积受到一定限制,对地基强度要求较高
5.桩基础设计计算与验算的主要内容？1.桩基础类型的选择 2.桩长,桩径的拟定及单桩容许承载力的估算 3.确定桩的根数及其平面布置 4.承台强度验算 5.单桩的内力计算与配筋 6.地基承载力的验算
1.简述抗震设防标准及防震措施？分为重力式(实体式)桥墩 桩(柱)式 柔性排架桩式
钢筋混凝土薄壁和空心薄壁式及轻型桥墩
2.选择地基处理方法时，需考虑哪些因素？1.地基条件2.建筑物结构条件3.施工条件
3.简述实体桥台的型式？:U型桥台,埋置式桥台,八字型桥台,拱型桥台等
４.柔性基础的特点是什么？整体性能较好,抗弯刚度可以相当大
５.桩基础设计计算与验算的主要内容？1.桩基础类型的选择2.桩长,桩径的拟定及单桩容许承载力的估算3.确定桩的根数及其平面布置4.承台强度验算5.单桩的内力计算与配筋6.地基承载力的验算
三、计算题（共20分）
有一桥台前墙如图，已知资料，填土γ=180KN/M3 Φ=30° H=10M车辆荷载为汽车-10级，无地下水；墙宽b=8M U=0.333试用朗金土压理论计算填土自重所引起对桥台的水平主动土压力。

X10=X1i=0.077+(19.929/19.929)N*(1-0.077)=1.000
Eohp=CiCzKhβ1γ1X10G0=1.3*0.33*0.20*0.485*1.0417*1.0*4736.02=205.30KN
2.某结构计算简图如下图，试计算横桥向水平地震Eohp.其中Ci=1.3 Ce=0.33 Kn=0.2 β1=0.485 γ1=1.0417 Χ1i=Χ5+(Hi/H) (1/3)*(1-X5) X5=0.077 G0=4736.02KN

解:X10=X1i=0.077+(19.929/19.929)N*(1-0.077)=1.000
Eohp=CiCzKhβ1γ1X10G0=1.3*0.33*0.20*0.485*1.0417*1.0*4736.02=205.30KN
1、重力式桥墩特点：靠自身重力来平衡外力。墩身厚实，可不用钢筋，用天然石材或片石混凝土砌筑。缺点是圬工体积大，自重和阻水面积大。
2、轻型桥墩的特点：刚度小，受力后允许在一定的范围内发生弹性变形，以钢筋混凝土为主。
3、桥墩按构造分类：实体重力式、实体薄壁式、空心墩、柱式、柔性排架桩墩、框架墩。
4、重力式桥台（U台）：墙背、台帽、前墙、基础、侧墙、锥形护坡。
5、轻型桥台：体积轻巧、自重较小，它借助结构物的整体刚度和材料强度承受外力，从而可节省材料，降低对地基强度的要求。
6、轻型桥台分类：1设有支撑梁的轻型桥台，又可分为一字型轻型桥台、八字型轻型桥台、耳墙式轻型桥台。2钢筋混凝土薄壁桥台（悬臂式、扶壁式、撑墙式及箱型式）；3加筋土桥台（内置式、外置式）；4埋置式桥台
7、桥墩最不利作用效应组合：a按桥墩各截面上可能产生最大竖向力的情况组合；b按桥墩各截面在顺桥向可能产生的最大偏心和最大弯矩的情况组合；c按桥墩各截面在横桥向可能产生最大偏心矩和最大弯矩情况组合。
8、重力式桥墩的计算内容有那些：1截面承载能力极限状态验算2桥墩的稳定性验算（抗倾覆、抗滑动稳定性验算）3相邻桥墩台均匀沉降差4基础底面特的承载力和偏心距验算。
9、桩柱式桥墩盖梁内力计算：在计算支点截面负弯矩时，采用非对称布置活载与恒载反力；在计算跨中正弯矩时，采用堆成布置活载与恒载反力。
10、柔性排架墩计算制动力时：各墩台受力按墩顶抗推刚度分配，由桥墩抗推刚度和橡胶抗推刚度组合而成。计算梁温度变形引起的水平力：无论温度升高还是降低，必然处在一个温度变化时偏移值等于零的位置（称温度中心），需先求出这个位置。
11、桥台的作用效应组合的布置：1仅在桥跨结构布置荷载2仅在台后破坏棱体上布置3都布置。
12、桥台作为竖向梁时强度验算：自重、填土本身引起的主动土压力（三角形）、车辆荷载引起的土压力（矩形）按台深上下铰接的简支梁计算。
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1、 扩大基础：将基础平面尺寸扩大以满足地基强度要求，这种基础称为扩大基础。
2、 刚性基础：当基础圬工具有足够的截面使材料的容许应力大于地基反力产生的弯曲应力和剪应力时，基础内不需要配置受力钢筋，这种基础称为刚性基础。（混凝土，粗石料）
3、 扩大基础的特点：比桩基与土体的接触面积更大，所以单位面积对土体的作用力较小，能承受较大荷载，对土层强度要求低；稳定性好、埋深较浅，施工简便。
4、 刚性角：自墩台身边缘处的垂线与基底边缘的联线间的最大夹角
5、 基础埋置深度的确定：确定基础埋置深度时必须综合考虑：1地基的地质和地形条件( 必须考虑把基础设置的地质条件良好，足够保证地基强度)；2河流的冲刷深度度（基础必须设置在设计洪水最大冲刷先以下不小于1m等）；3还要考虑当地的冻结深度（基础必须埋置在最深冻结线以下不小于0.25m等）；4上部结构的形式（上部结构的形式不同，对基础产生的位移要求也不同）；5保证持力层稳定所需要的最小埋置深度（必须考虑把基础设置在变形较小，而强度又比较大的持力层上）。
6、 刚性扩大基础验算的内容：地基承载力验算（持力层强度或软弱下卧层承载力验算）、基底合力偏心距验算、基础稳定性和地基稳定性验算、基础沉降验算。
7、 为什么要进行基底合力偏心距的验算：其目的是尽可能使基底应力分布比较均匀，以避免基底两侧应力相差过大，使基础产生较大的不均匀沉降，导致墩台发生倾斜，影响正常使用。
8、 旱地上基坑开挖围护方法：板桩墙支护、喷射混凝土支护、混凝土围圈护壁
9、 基坑排水方法：表面排水法：此方法设备简单、费用低，一般土质条件下均可采用。但当地基土为饱和粉细沙土等粘聚力较小的细粒土层，如粉质土、粉沙类土时，由于抽水会引起流沙现象，造成基坑的破坏和坍塌，此时可采用井点法降低地下水位。
10、水中基坑开挖：土围堰和草袋围堰、钢板桩围堰、双臂钢围堰、地下连续墙围堰。
11、板桩墙的作用：挡住基坑四周的土体，防止土体下滑和防止水从坑避周围渗入或从坑底上涌，避免渗水过大或形成流沙影响基坑开挖。
12、板桩墙计算的内容：计算侧向压力、确定入土深度（稳定性）、计算板桩墙截面内力（验算材料强度，尺寸）、支撑计算、基坑稳定行验算（坑底流砂验算、基坑隆起验算）、封底混凝土厚度计算 坑底流砂：若坑底为粉砂、细砂等时，在基坑内抽水可能引起流砂现象；基坑隆起：开挖较深的软土基坑时，在坑壁土体自重和坑顶荷载作用下，坑底软土可能受挤在坑底发生隆起。
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1、桩基础的特点：具有较高的承载力、稳定性好、沉降量小而且均匀、在深基础中具有耗用材料少、施工简便等特点。
2、桩基础的适用条件：1荷载较大，地基图层软弱，持力层位置较深；2河床冲刷大3对沉降要求敏感4结构需承受较大水平荷载时5施工水位较高时6地震地区，在可液化地基中，可提高抗震能力；
3、桩基础的分类：1按承台位置：高桩承台基础，低桩承台基础；2按设置效应：挤土，部分挤土，非挤土；3按桩土相互作用：竖向受荷桩（摩擦、端承），横向受荷桩（主动、被动、竖直、斜）；4按施工方法：沉桩（打入桩、振动下沉桩、静压力桩），灌注桩（钻挖孔灌注、沉管灌注），管柱基础，钻埋空心桩。
4、钻孔灌注桩的施工工序：1准备工作，如准备场地、埋置护筒、制备泥浆和安装钻机钻架等；2钻孔，先选择钻孔的方法和钻具，应注意钻孔时容易发生的问题，如塌孔，缩孔等；3清孔及吊装钢筋骨架；4灌注水下混凝土
5、钻孔注意事项：1始终保持钻孔护筒内水位高出筒外1~1.5米，并保证护壁泥浆的质量；
2根据土质情况控制钻进速度、调整泥浆稠度，防止塌孔、斜孔、卡钻；3钻孔应一气呵成，不应中途停钻以避免塌孔；4应加强对桩位、成孔情况的检查工作。
6、灌注水下混凝土（直升导管）的注意事项：1混凝土拌和必须均匀，减少中途运输的距离；2灌注必须一气呵成；3灌注过程要随时测量孔内混凝土标高和导管入孔长度，并及时调整；4灌注桩顶标高应比设计值预加一定高度，最后应人工凿除。
7、单桩轴向荷载传递机理：当竖向和在施加与桩顶，桩侧就会受到土的向上摩阻力，随着载荷的增加，桩身压缩和位移量增大，桩身下部饿摩阻力随之调动起来，桩底土层也因受到压缩而产生桩端阻力，直到桩侧摩阻力达到极限，荷载全部由桩端阻力承担，最后直至桩端阻力达到极限而破坏。此时桩所受的荷载就是桩的极限承载力。
8、桩侧和桩底摩阻力的影响因素：桩与土之间的相对位移，土的性质，桩的刚度，时间因素，土中应力状态和桩的施工方法有关。 桩底阻力的影响因素：土的性质，持力层上的覆荷载，桩径，桩底作用力，时间和桩底进入持力层深度有关。
9、负摩阻及其危害：当桩周围土体因某种原因发生下沉，其沉降变形大于桩身变形时，在桩侧表面将出现向下作用的摩阻力，称其为负摩阻力。负摩阻力的发生将使桩侧土的部分重力传递给桩，从而会使桩的承载能力降低，沉降加大。
10、负摩阻产生的原因：桩附近地面大量堆载，引起地面沉降；因地下水位、桩穿过欠压密土层、桩群密集产生的超孔隙水使土层产生自重固结下沉；黄土湿陷、冻土融化产生的地面下沉。
11、文克尔假定：梁身任一点的土抗力和该点的位移成正比。 确定地基系数 C的方法“m”法：假定地基系数C随深度呈线性增长， C=mz。 还有 K法，c法，常数法。
12、桩的换算宽度：桩在水平外力作用下，除了桩身宽度范围内桩侧土受挤压外，在桩身宽度以外的一定范围内的土体都受到一定的影响，将桩的设计宽度换算成相当实际工作条件下矩形截面桩的宽度，这个宽度称为换算宽度。
13、单排桩的计算步骤：1计算各桩桩顶多承受的荷载P、Q、M；2确定桩在最大冲刷线下的入土深度即桩长；3验算单桩轴向承载力；4确定桩的计算宽度；5计算桩—土变形系数；6计算地面出桩截面的作用力Q0、M0，然后计算个截面的内力；7计算并验算桩顶位移和墩台顶位移；
14、单桩刚度：对于多排桩，当第i根桩桩顶产生单位位移或转角时，在桩顶引起的内力大小叫单桩刚度。
15、群桩效应：摩擦型群桩基础受竖向荷载后，由于承台、桩、土的相互叠加作用使其桩侧阻力、桩端阻力、沉降等性状发生变化而与单桩明显不同，这种群桩所产生的效应。。。
16、桩基础类型的选择：选择桩基础类型时，应根据设计要求和现场条件，并考虑各种类型的桩具有的特点，综合分析选择。1承台底面标高的考虑，低承台稳定行好，但在水中施工难度大，高承台施工方便，但稳定性差，不能承受较大的水平力和弯矩。2端承型和摩擦型的考虑，端承桩基础承载力大，沉降小，当基岩埋置较浅时，多用端承桩，深时，用摩擦桩。3与施工方法的考虑。
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1、沉井基础：它是以井内挖土，依靠自身重力克服井壁摩阻力后下沉对哦设计标高，然后经过混凝土封底并填塞井孔而成的井筒状深基础。
2、沉井基础的特点：埋深可以很大，整体性强，稳定性好，有较大的承载面积，能承受较大的垂直荷载和水平荷载，沉井即是基础，施工时又是挡土围堰结构，使施工工艺简便。
3、沉井的分类：1按施工方法：一般沉井、浮运沉井。2平面形状：圆形、圆端型和矩形；立面形状：竖直式、倾斜式和台阶式。3建筑材料分：混凝土沉井、钢筋混凝土沉井、竹筋混凝土沉井和钢沉井。
4、沉井的构造：井壁、刃脚、隔墙、井孔、凹槽、射水管、封底和盖板。
5、沉井的施工工序：1旱地上沉井施工：平整场地、制造第一节沉井、拆模及抽垫、挖土下沉、接高沉井、筑井顶围墙、地基检验和处理、封底填充井孔及教主顶盖 2筑岛法：水流不大，水较浅。3浮运沉井施工：水深较大，
注意事项和处理：1沉井发生倾斜和偏移：土质松软、软硬不均匀，导致沉井下沉不均匀；挖土不对称；井内发生流沙等，因施工过程中随时观察沉井的位置和方向，发现过大偏差及时分析和修正。2沉井下称困难：主要是由于自身重力克服不了井壁摩阻力，或刃脚遇到大的障碍物所致。应增加沉井自重并减小井壁摩阻力。
6、沉井施工过程中的验算：1自重下沉验算；2第一节沉井的竖向挠曲验算；3沉井刃脚受力验算；4井壁受力计算；5混凝土封底及顶盖的计算。
7、针对软弱地基处理的目的：提高地基的抗剪强度，增大地基承载能力，防止剪切破坏和减轻土压力；改善地基压缩性能，减少沉降和不均匀沉降；改善渗透性能，加速固结沉降过程；改善土的动力性，防止液化；消除或减少土的不良工程特性
8、地基处理的方法：1物理：置换、排水、挤密、加筋；2化学：搅拌、灌浆；3热处理：热加固、冻结。
请删除O(∩_∩)O谢谢： Foreigners flock to China's 'porcelain capital' Preserving the ancient traditions Foreigners flock to China's 'porcelain capital' Jingdezhen raises porcelain standard City's long history of fine ceramics lures followers from across the world, report Peng Yining and Hu Kaiyong in Jingdezhen, Jiangxi province. Dressed in paint-stained coveralls, China De La Vega easily navigated the maze of alleyways running alongside a ceramics factory in Jingdezhen, Jiangxi province.
The 31-year-old Australian potter and painter wound her way through armies of one-meter-high ceramic Buddhas and piles of porcelain shards while nodding greetings to the workers and residents. She said the locals are used to seeing foreigners in Jingdezhen, China's "porcelain capital", where fine ceramics have been produced for more than 1,700 years, attracting numerous "porcelain pilgrims" from across the globe. Unlike huge Chinese metropolises such as Beijing and Shanghai, Jingdezhen is a prefecture-level city with no "bar streets" or international stores that are popular among expatriates. But despite its lack of Western chain stores, Jingdezhen is one of the most international cities in inland China, with ceramic studios owned by foreigners dotting the streets, the surrounding countryside and even remote mountaintops. When she first visited the city in 2011, De La Vega was impressed by the discarded pieces of porcelain she found lying around. "I dug out many pieces from the soil around the ceramics works - all the old Buddha heads, hands and feet, which I rebuilt into new sculptures and used in my next exhibition in Australia," she said. "I love this place because the process of making ceramics is a very peaceful one." Visa-free policy brings Chengdu biz, tourism boost. Making national headlines several times, Chengdu's 72-hour visa-free policy has attracted wide attention from both Chinese and foreign experts and businessmen since it took effect on Sept 1 last year. The program permits citizens from 51 countries and regions including the United States, Australia, Canada and Japan who have valid visas and flight tickets to a third country to spend three days in the city. The capital of Sichuan province is the first city in the western region of China to offer foreign tourists a three-day visa and the fourth nationwide to adopt the policy following Shanghai, Beijing and Guangzhou. Li Zhiyong, deputy dean of the tourism institute at Sichuan University, said the move "contributes to a large increase in the number of overseas tourists and raises the city's level of internationalization". "The policy will also bring direct economic revenue," Li said. "Chengdu has many cultural legacies and is also a paradise for panda lovers with the world's largest breeding and research center. Three days are long enough for foreign visitors to visit those iconic tourist spots," he noted. The city is home to the remains of the Jin sha civilization that dates back more than 3,000 years as well as the Qing cheng Mountains and the Du jiang yan irrigation system. Qing cheng has long been recognized as the birthplace of Taoism, China's ancient indigenous religion, while Du jiang yan is considered to be the oldest functioning water-control project in the world. Chengdu ranked third in tourist facilities, management and services among 60 Chinese cities in a customer satisfaction survey released last year. But, Li added that efforts are still needed to develop more tourism products, improve English services and provide accurate translation of traffic signs and scenic billboards. Zhao Yun, chairwoman of British Chamber of Commerce Southwest China, told China Daily that his colleagues found the policy very convenient. "A British client once flew here and stayed for just one day to check her ordered goods," she said. Zhao was born in Shanxi province, but she has lived in Chengdu for more than 10 years. "My life was like a running race moving from place to place. I also lived in Beijing and Shanghai before," she said. "But Chengdu is a place that you never want to leave once settling down. It is now my second hometown," she said. If the environment is further improved, the city will attract more people to visit and live, with the 72-hour visa-free policy and compelling conditions in transportation, culture, climate and cuisine, he said. Foreigners also gave positive feedback on the policy. A spokesman from Dell Inc said the company has a global hub of operation in Chengdu, so the three-day visa "has an immediate and positive influence on the company's business development". Rudy Buttignol, president of the public broadcasting company in British Columbia, Canada, said his work requires frequent travel to Chengdu and the policy "makes the trips easier". Data from the city's public security bureau shows some 100 foreign visitors enjoyed the 72-hour policy by the end of March, most of them from the United States, the United Kingdom and Germany. Chengdu also reported robust growth in its overall tourist industry last year. Official statistics show that it received some 150 million tourists last year, an increase of 28 percent from 2012. Around 1.7 million came from abroad, an increase of 12 percent. Total revenue from tourism surpassed 133 billion yuan ($21.7billion). During his visit to Kazakhstan in September, Chinese President Xi Jinping proposed that China and Central Asia join hands to build a Silk Road economic belt to boost cooperation. The idea has been widely echoed in Central Asian countries, becoming an encouraging blueprint for Chinese areas along the Silk Road that has linked Asia and Europe for more than 2,000 years. In the next three weeks, China Daily reporters will travel through the belt in China and in Kazakhstan, Uzbekistan and Turkey. They will show the progress and expectations of the countries, businesses and peoples on the route. Shaanxi - the start of the ancient Silk Road - has positioned itself as the new starting point for the development of the Silk Road Economic Belt, which will strengthen China's cooperation with Central Asian countries, a senior official said. Shaanxi Governor Lou Qinjian said the province is fresh, rich and unique, as it was when it anchored one end of the ancient Silk Road. "It is the best option for accommodating industrial transfers from East China or the world at large," he said on Wednesday in Xi'an. Lou held a joint interview with 27 media, including China Daily, the first in a series of interviews entitled Chinese Media Along the Silk Road. The interviews will be in Shaanxi and Gansu provinces and the Xinjiang Uygur autonomous region, as well as Kazakhstan, Uzbekistan and Turkey. The media group held the first interview on Wednesday morning in Xi'an, the starting point of the ancient Silk Road, a trade channel established more than 2,000 years ago linking China, Central Asia and Europe.
The pursuit of beauty is a common goal for most women, whether they live in the modern world today or in the modest times of the past. The pursuit of beauty is also a life-long journey, something that demands pe rseverance and commitment.
Summer is here, and so are the hot temperatures, humid air and harmful UV rays. Most Chinese women perfer fairer complexions, which means they have to do more work to stay beautiful during the hottest time of the year.
However, without SPF50 sunscreens and air conditioned rooms, how did women in ancient China cope with the heat and remain beauty-conscious?  In this article, you'll discover that aside from today's botox and face lifts, there are much more that ancient wisdom has to offer.