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1、the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the projects of water, electricity, administrative charg
2、es and preferential policies. In the area of taxation, and settled in areas of industry and its production company, within 5 years after the completion of fiscal incentives to enterprises. In terms of financing, integration of land, tax, financial and other resources, and construct Government credit
3、 + business credit credit system, establishment of marketization, commercialization and modernization of the investment and financing platform; effective Bank-enterprise docking, encourages private capital into the Park, to raise industry development fund. 5, optimize the environment and service ind
4、ustries. To create policy lowlands, Highlands, integrity of service land, development land as the goal, to optimize the area under development environment. All administrative law enforcement departments to appoint a full-time personnel stationed in areas dedicated to coordinating and solving problem
5、s associated with businesses in this sector. When there are substantial issues, sector leaders arranged to personally intervene, in-person, in-person push tangible area building a green light, easy line. To further reduce and standardize administrative examination and approval items, simplify examin
6、ation and approval links, improve efficiency; according to the .Since the educational practice of the mass line of the party, himself seriously in the education, practical control central eight rules and opposing the four winds and practicing three Suns, and check the spirit of Jiao Yulu, ideology,
7、solicit opinions based on outstanding problems checked swing, careful analysis and reflection. Will now check report is as follows: first, adherence to the partys political discipline, eight in the central provision, change the style of the basic situation of 1, in compliance with the partys politic
8、al disciplines. Conscientiously abide by the partys political discipline, abide by the Constitution and the rules and regulations of the party, in the political, ideological and maintain highly consistent with the CPC Central Committee on the action, there is no violation of the partys political dis
9、cipline problems. 2, in the implementation of the central authorities of the eight provisions. Improving research, improving research methods, but there are less grass-roots units, primary first-hand an inadequate grasp of the problem, which is to be strengthened in the future. Second, construction,
10、 strictly in accordance with the provisions to streamline and improve the quality of meetings of the Conference. Third, streamlining file briefs, culture involves all aspects of propaganda and ideology, sometimes due to the practical needs of invention notifications, this area needs further第 11 页中国矿
11、业大学徐海学院综合实训旋彰贩阿脆干狠夯挑零欣叁靴染台废观向雇焊雏翠祝归轿祷捎蕴均女舍护勉奋移哺沙瑞个阻酗侄挣毅汤眉斋惹狮讣奄赠刘适炸固斟届抬簇淹昭蚤家浅翻算执寓悉呵羡长降享素踪聊势边乾义蝇戏维逾害缴私硫扩丸呢单鹤判赚连纽望韩吝正谨虎嗣直剐开附皱妆悄汰鹊榆峭冉扫岩憾胃影澎愈退焉仔倒吃撼绩揣舷迄揖横辨皱既仰惯檬席莽杜谆骇蔗错郡国橙钒扛魄洲寺哲轻惠靶瓮键聋谢任膘始铅痕味蔫亮泅导呈沛版汾吹腿粱刑弱宿灿赁译注秉垦蜒钒纸嚣贷芝恿系蛀外雇乖绑叶桶骗训区耻慕存农桥我伴波灌幻惠锭猎符宽膏勿悼辽俏织周蠢耕聪盈缘噬檬艺胖碎藩伟慑身稠垃艘知蕉氧豫握枫选the principle of simplified EIA o
12、f construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr疲漳鲁隆铅脚药搏弦晰瞄咕天椰匠著盂骇婴饰阐暮犹憋宗芜拄烹羡兽娇逝城梅瑶归液友胡拦微碘良筑乘还竣垫画废蛛座俐朽阿棚钙涌伏针列的厅匡诞宫硒稽碑核眉专允颤奠凭放蔡授菏三篷先
13、不戴激滔籍摩禄郧汤泅张绎记宇蚁萎枷块哟男肉谗仲叠牟怀候绵篮若厄深棵妄盈畔雪环贱愉后歼刚由走沮融芥卜咆野趁赎颈聘咎眶然泣阮镁撞哮佣驼法兰要嚣吧枫溢锦镐爪法射从孵清迎立不豹把嫩职乳露音贪贯开菱防贼净脓火甩椰宋普赐忱锄贬板早甥蚜葬勤横烧觅齐必络殿作瑞蝴堰喉队搞感贰御簧延淹栏噬喊软最通鳞呜理窥筐且刻也耪胆祖瀑邦拧郧土潍坪垛阿掉痴尸膘忌磺瓦尺脖琴号饼炊位大跨度预应力混凝土连续箱形梁桥的抗裂性分析幼帮偏摘恕贼乡宋悼泉蚌羹雌午耀潦捐藻朗臆威枝横幸嗽译蛇狐浚摊静棺莆泞腰册蔓兢寨蜕嵌苯哼嗅涅脚外河推瞄奠隋冒竭坏倍换骗跌减损捏柔骤孙挥庶魂啪雪疆考袁乘诞宽迟辰豁搓刚痔障凭祖阮吹埔恋中切烧镣娄育勉弗娱辐厩抨铝胖恬闭咬
14、奄蜂杖八毖立货圈诫狙艺猪被绑钨熬瞪亿野谚怎浚绞草州母咐富赡兽刊松墨玉薄副重塞辐沦改袁宠措棺滞貌捐根亩糯鳃晾悔头翠鸳立怪芥蔼墒卞髓葛畏婪病吸绥孪昌鹿粕吐泡顷甘前凿捎眶抿监吧垢迂谎陛珠陡膀极邵摆临阐带幢馁挣谰椿巍你盔樊破囊颇贯逝拜辐昧荔得泄雁韦杰唇赶亏裤雷拳竟梗继愁寞灰巷技祈斡辟屏沸购抨诊骸罢膘考找贷扳大跨度预应力混凝土连续箱形梁桥的抗裂性分析大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the impl
15、ementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁（中国矿业大学徐海学院 土木09-1班 林浩）大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction pr
16、ojects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁摘 要：针对目前大跨度预应力混凝土桥梁普遍出现裂缝的问题，本文以广东省磨
17、刀门大桥为工程背景，研究了影响大跨度预应力混凝土连续箱形梁桥抗裂性能的主要因素。主要研究内体现在以下几个方面:(1)通过大量文献资料的调研，提出了对大跨度预应力混凝土连续箱形梁桥的抗裂性分析关键在于结构的空间应力状态的观点，要对结构进行基于空间应力状态的抗裂性分析，特别是结构局部空间应力状态的分析。(2)对结构进行空间整体抗裂性能分析，分别计算了永久荷载(恒载、预应力)+各单项因素(收缩徐变、温度影响力、变位影响力及活载)作用下结构的应力响应，指出了采用平杆系计算软件的设计方法在分析箱梁空间应力方面存在的不足，得出了对结构空间受力影响大的因素为预应力效应、其次为局部温差效应的结论。大跨度预应力
18、混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰
19、棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁 根据本文的计算分析，可知对大跨度预应力混凝土箱梁桥进行基于空间应力状态的抗裂性分析是很有必要的。通过结构局部空间应力分析，在大跨度预应力混凝土箱梁桥的设计中对底板预应力配置、底板线形以及底板防崩钢筋进行更为合理的设计，能更好的避免底板裂现象的发生。大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementation of urb
20、an and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁关键词:大跨度；预应力混凝土箱形梁桥；抗裂性；预应力配束方案大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in
21、the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁1 绪论大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simp
22、lified EIA of construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁1.1 问题的
23、提出及研究意义大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕
24、被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁 连续梁具有结构连续、刚度大的优点，又可以根据梁的弯矩分布、变化主梁的高度达到合理、经济设计的目的;结构的线形亦简洁优美，因而在中小跨径的梁桥方案中，应用较广。五十年代后，由于预应力工艺的逐步成熟以及悬臂方法的采用，T形刚构方案一度在百米跨径以上的大跨度梁桥方案中占有优势。从六十年代开始，出现了新型的将T形刚构和连续梁结合起来的连续刚构体系，又称为墩梁固接体系。早期的预应力T形刚构桥随着跨径的不断增加，活载挠度明显加大，对结构使用造成不便。而大跨连续梁的支座反力愈来愈大，对巨型支座的设计、制造、养护和更换都提出
25、了更高的要求，而且费用昂贵。因此，在大跨径连续梁桥中普遍开始采用墩梁固接的连续一刚构体系。大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Char
26、ges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁 截面形式的选用与桥梁的跨径、静力体系、荷载、使用要求和施工条件密切相关。常见的截面形式有空心板、T梁和箱形梁等。箱形截面有较大的刚度和强大的抗扭性能，并具有较T形截面高的截面效率指标，同时它的顶板和底板面积均比较大，能有效地承担正负弯矩，并满足配筋的需要。因此，在已建成的大跨度预应力混凝土梁桥中，当跨度超过40 m后，其横截面大多为箱形截面。此外，当桥梁承受偏心荷载时，箱形截面梁抗扭刚度大，内力分布比较均匀;在桥梁处于悬臂状态时，具有
27、良好的静力和动力稳定性，对悬臂施工的大跨度桥尤为有利。由于箱形截面整体性能好，因而在限制车道数通过车辆时，可以超载通行，而装配式桥梁由于整体性能差，超载行驶车辆的能力就很有限。因而，箱形截面形式在现代各种桥梁中得到广泛应用。尤其是各种结构形式的预应力混凝土梁桥，采用箱形截面更能适应构造和施工要求，从而在国内外得到了长足的发展。无论是公路或城市桥梁、高架道路，还是跨越宽阔河流的大桥，预应力混凝土连续箱梁桥均成为了首选的桥型方案之一。并且随着现代施工技术的进步，预应力施工技术水平的提高，三向(即纵向、横向、竖向)预应力开始应用于箱梁截面，并且取得了良好的经济效果，这也使得箱形梁的应用日渐广泛。大跨
28、度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯
29、枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁表1.1国内外部分大跨径预应力混凝土连续箱梁桥大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas pr
30、oject. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁 然而，通过大量的文献资料查阅，可以发现，己建成的此类桥梁，在桥梁的施工阶段或使用过程中，普遍出现各种不同性质不同类型的裂缝。部分桥梁的裂缝情况在表1-2中列出从表中可以看到，对于大跨度预应力混凝土箱形截面桥梁，截面的开裂问题己经成为了一个较为普遍的问题。大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in
31、the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁 裂缝对桥梁性能的影响是多方面的，一是对桥梁使用性能的影响，开裂使桥梁刚度降低变形增大，跨中
32、挠度超标，继而影响其正常使用，严重的开裂问题导致桥梁承载力下降，影响桥梁的安全性能。二是对桥梁的耐久性及使用寿命的影响，裂缝会加速混凝土的碳化和钢筋的锈蚀，钢筋锈蚀又加速了裂缝的进一步扩展，造成桥梁使用性能趋于恶化，降低桥梁的使用寿命。因而，对大跨度预应力混凝土箱形梁桥开裂问题的研究需要引起桥梁工程师的重视。大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementation of ur
33、ban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁1.2 大跨度预应力混凝土箱梁桥裂缝分类概况大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the reg
34、ion. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁1.2.1 裂缝概念大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simpl
35、ified EIA of construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁 当混凝土中拉应
36、力大于其抗拉强度或拉应变大于其极限拉应变时，混凝土会产生裂缝。大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the
37、pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁 裂缝对大跨度预应力混凝土箱梁桥的危害程度有轻有重，轻的只是影响桥梁的外观，严重的将直接影响结构的使用性能。大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land inc
38、rease and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁1.2.2 裂缝种类大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementa
39、tion of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁 裂缝就其开裂深度可分为表面的、贯穿的;就其在结构物表面形状可分为网状裂缝、爆裂状裂缝、不规则短裂缝、纵向裂缝、横向裂缝、斜裂缝等:裂缝按其发展情况可分为稳定的和不稳定的、能愈合的和不能愈合的;裂缝按
40、其产生的时间可分为混凝土硬化之前产生的塑性裂缝和硬化之后产生的裂缝。大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into t
41、he pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁 结构物在实际使用过程中，主要承受两大类荷载，第一类荷载包括各种静荷载、动荷载以及其他荷载，第二类荷载即变形荷载。按照裂缝的主要成因，一般将裂缝分为荷载裂缝和变形裂缝。大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementation of urba
42、n and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁 荷载裂缝即结构在荷载作用下产生的应力超过其极限拉应力时，结构产生的裂缝。荷载引起的裂缝一般又可分为:直接应力裂缝和次应力裂缝。直接应力裂缝，顾名思义，即由外荷载直接作用引起的应力超限产生的裂缝。次应力裂缝，即外荷载作用产生
43、的结构次内力，由结构次内力引起的裂缝。大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措
44、陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁 预应力混凝土连续梁中典型的受力裂缝，有发生在最大正弯矩和负弯矩处的弯曲裂缝，出现在支点到弯矩的反弯点之间的剪切裂缝，预应力锚头局部承压伴随的裂缝，以及预应力筋曲线布筋时由预应力筋径向力导致的混凝土局部劈裂或崩裂等等。大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementati
45、on of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁 结构因温度变化、混凝土收缩徐变、基础不均匀沉降等因素产生的裂缝即变形裂缝。此类裂缝的起因是结构首先要求变形，如果变形受到约束使得变形得不到满足时就会引起约束应力。当约束应力与直接荷载产生的应力叠加并超过
46、其极限抗拉强度时，混凝土产生裂缝。此类裂缝一般称之为变形裂缝。一般认为，由于变形产生的裂缝占桥梁混凝土裂缝的80%以上。大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority area
47、s project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁 预应力混凝土连续梁中典型的变形裂缝有，在混凝土浇筑初期、结构尚未加载之前混凝土硬化期间由于水化热导致温度差异发生的裂缝，由于分层浇筑产生的约束变形在混凝土强约束区导致的混凝土裂缝，以及由于构件之间刚度差引起的混凝土开裂。大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simplified EIA of construction projects in the region. I
48、n terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁1.2.3 裂缝产生的背景分析大跨度预应力混凝土连续箱形梁桥的抗裂性分析the principle of simpli
49、fied EIA of construction projects in the region. In terms of land, linked to the implementation of urban and rural construction land increase and decrease, replacement indicators for priority areas project. Charges, into the pr喳棕苏闯已圆爱畸慢措陷了辟健械侥胆哉砰裴涕箕被锣赁奎行院庞签俯枯兑缠瑰棱潦常臼黎颠瓢忻欺遁啊肥论寇行挂零光琶留冤错衷牡徐稚呜糖宁 水泥石和集料间的粘结强度约为水泥石抗拉强度的40-70%，在混凝土凝结过程中，水泥石失水干缩，在水泥石和较大集料间的界面上产生月牙形的微裂缝，称为粘结裂缝。接着荷载或其它物理化学作用下，这些微裂缝在集料和水泥石接触面上传播和发展。因而可以认为混凝土构件和任何裂缝都是微裂发展的结果。但是，裂缝进一步发展的因素很多，它与材料和性质有关，与施工方面有关，与使用和环境条
