《w钻孔灌的注桩后压浆法桩端地基加固施工技术.doc》由会员分享，可在线阅读，更多相关《w钻孔灌的注桩后压浆法桩端地基加固施工技术.doc（9页珍藏版）》请在三一办公上搜索。
1、 钻孔灌注桩后压浆法桩端地基加固施工技术 摘要： 叙述了灌注桩后压浆适用的地质条件，加固机理，参数的确定，施工工艺及在实际工程中的应用。 关键词： 灌注桩 压浆参数 施工技术 近年来我国的高层建筑迅猛发展， 对地基承载力的要求越来越高，基础形式一般采取灌注桩基础，为了满足设计要求，灌注桩的持力层要求是较为完整的岩石层，桩长和桩径尺寸往往做的很大，使得地下部分的造价在整个工程总造价中占有较大的份额，同时，由于桩长很长，给施工造成很大的困难。在我国有些地区，地貌属于山前冲积平原单元，地质在穿过粘土层后，是一层较厚的碎
2、石层，能否将这一地层加固，达到设计要求，作为基础的持力层呢？ 基于这种考虑，我国设计和施工工作者经过多年的探索和实践，总结了一套钻孔灌注桩后压浆法加固桩端地基的方法，大大缩短了桩长，取得了良好的经济效益。 1 适用的地质条件 本文介绍的施工方法适用于灌注桩的持力层应为碎石层，碎石含量应在50 %以上，充填土与碎石无胶结或者为轻微胶结，碎石的石质要坚硬，碎石分布均匀，碎石层厚度要满足设计要求。 2 加固机理 在灌注桩施工中将钢管沿桩钢筋笼外壁埋设， 桩混
3、凝土强度满足要求后，将水泥浆液通过钢管由压力作用压入桩端的碎石层孔隙中，使得原本松散的沉渣、碎石、土粒和裂隙胶结成一个高强度的结合体。水泥浆液在压力作用下由桩端在碎石层的孔隙里向四周扩散，对于单桩区域，向四周扩散相当于增加了端部的直径，向下扩散相当于增加了桩长；群桩区域所有的浆液连成一片，使得碎石层成为一个整体，从而使得原来不满足要求的碎石层满足结构的承载力要求。在钻孔灌注桩施工过程中，无论如何清孔，孔底都会留有或多或少的沉渣；在初灌时，混凝土从细长的导管落下，因落差太大造成桩底部位的混凝土离析形成“虚尖”、“干碴石”；孔壁的泥皮阻碍了桩身与桩周土的结合，降低了摩擦系数，以上几点都影响到灌注桩
4、的桩端承载力和侧壁摩阻力。浆液压入桩端后首先和桩端的沉渣、离析的“虚尖”、“干碴石”相结合，增强该部分的密实程度，提高了承载力；浆液沿着桩身和土层的结合层上返，消除了泥皮，提高了桩侧摩阻力，同时浆液横向渗透到桩侧土层中也起到了加大桩径的作用。以上几点均对提高灌注桩的单桩承载力起到不可忽视的作用。 3 压浆参数的设定 压浆参数主要包括压浆水灰比、压浆量以及闭盘压力，由于地质条件的不同，不同工程应采用不同的参数。在工程桩施工前，应该根据以往工程的实践情况， 先设定参数，然后根据设定的参数，进
5、行试桩的施工，试桩完成后达到设计的强度，进行桩的静载试验，最终确定试验参数。 （1） 水灰比水灰比一般不宜过大和过小，过大会造成压浆困难，过小会使水泥浆在压力作用下形成离析，一般采用015017 . （2） 压浆量压浆量是指单桩压浆的水泥用量，它与碎石层的碎石含量以及桩间距有关，取决于碎石层 的孔隙率，在碎石层碎石含量为50 %70 % ，桩间距为45m 的条件下，压浆量一般为115210t .它是控制后压浆施工是否完成的主要参数。 （3） 闭盘压力闭
6、盘压力是指结束压浆的控制压力，一般来说什么时候结束一根灌注桩的压浆，应该根 据事先设定的压浆量来控制，但同时也要控制压浆的压力值。在达不到预先设定的压浆量，但达到一定的压力时就要停止压浆，压浆的压力过大，一方面会造成水泥浆的离析，堵塞管道，另一方面，压力过大可能扰动碎石层，也有可能使得桩体上浮。一般闭盘的最大压力应该控制在018MPa . 根据预先设定的参数，进行试验桩的施工，再根据试桩的静载试验结果，最后确定工程桩的压浆参数，就可以进行工程桩的施工了。 4 后压浆施工工艺
7、 411 施工工艺流程 灌注桩成孔钢筋笼制作压浆管制作灌注桩清孔压浆管绑扎下钢筋笼灌注桩混凝土后压浆施工 412 施工要点 （1） 压浆管的制作在制作钢筋笼的同时制作压浆管。压浆管采用直径为25mm 的黑铁管制作，接头采用丝扣连接，两端采用丝堵封严。压浆管长度比钢筋笼长度多出55cm，在桩底部长出钢筋笼5cm，上部高出桩顶混凝土面50cm 但不得露出地面以便于保护。压浆管在最下部20cm制作成压浆喷头（俗称花管） ，在该部分采用钻头均匀钻出4 排（每排4 个） 、
8、间距3cm、直径3mm的压浆孔作为压浆喷头；用图钉将压浆孔堵严，外面套上同直径的自行车内胎并在两端用胶带封严，这样压浆喷头就形成了一个简易的单向装置：当注浆时压浆管中压力将车胎迸裂、图钉弹出，水泥浆通过注浆孔和图钉的孔隙压入碎石层中，而混凝土灌注时该装置又保证混凝土浆不会将压浆管堵塞。 （2） 压浆管的布置将2 根压浆管对称绑在钢筋笼外侧。成孔后清孔、提钻、下钢筋笼，在钢筋笼吊装安放过程中要注意对压浆管的保护，钢筋笼不得扭曲，以免造成压浆管在丝扣连接处松动，喷头部分应加混凝土垫块保护，不得摩擦孔壁以免车胎破裂造成压浆孔的堵塞。按照规范要求灌注混凝土。&nbs
9、p; （3） 压浆桩位的选择根据以往工程实践，在碎石层中，水泥浆在工作压力作用下影响面积较大。为防止压浆时水泥浆液从临近薄弱地点冒出，压浆的桩应在混凝土灌注完成37d 后，并且该桩周围至少8m 范围内没有钻机钻孔作业，该范围内的桩混凝土灌注完成也应在3d 以上。 （4） 压浆施工顺序压浆时最好采用整个承台群桩一次性压浆，压浆先施工周圈桩位再施工中间桩；压浆时采用2 根桩循环压浆，即先压第1 根桩的A 管，压浆量约占总量的70 %（111114t 水泥） ，压完后再压另1 根桩的A 管，然后依次为第1 根桩的B 管和第2 根桩的B 管，
10、这样就能保证同一根桩2 根管压浆时间间隔3060min 以上，给水泥浆一个在碎石层中扩散的时间。压浆时应做好施工记录，记录的内容应包括施工时间、压浆开始及结束时间、压浆数量以及出现的1异常情况和处理的措施等。 5 压浆施工中出现的问题和相应措施 （1） 喷头打不开压力达到10MPa 以上仍然打不开压浆喷头，说明喷头部位已经损坏，不要强行增加压力，可在另一根管中补足压浆数量。 （2） 出现冒浆压浆时常会发生水泥浆沿着桩侧或在其他部位冒浆的现象，若水泥浆液是在其他桩或者地面上冒出，说明桩底已
11、经饱和，可以停止压浆；若从本桩侧壁冒浆，压浆量也满足或接近了设计要求，可以停止压浆；若从本桩侧壁冒浆且压浆量较少，可将该压浆管用清水或用压力水冲洗干净，等到第2 天原来压入的水泥浆液终凝固化、堵塞冒浆的毛细孔道时再重新压浆。 （3） 单桩压浆量不足压浆时最好采用整个承台群桩一次性压浆，压浆先施工周圈桩形成一个封闭圈，再施工中间，能保证中间桩位的压浆质量，若出现个别桩压浆量达不到设计要求，可视情况加大临近桩的压浆量作为补充。 6 结语 不同的工程地质条件有很大的差异， 不可能有相同的压浆参
12、数，预先设定的压浆参数往往参考相似工程的经验，压浆参数的最终确定要依赖于试验桩的结果，而全国可以借鉴的经验并不多，有待进一步的积累，再加上理论的探讨，最终形成一个成熟的技术。灌注桩后压浆具有提高单桩承载力，提高生产率，节约建设资金的优点，所以，在具备条件的工程中推广后压浆施工工艺有着重要的意义和广阔的前景。/Porganization system and working mode, the selection of a number of municipal strengthening group to build innovation and strengthen the organiza
13、tion of the basic level organizations advanced model.(seven) the manual work of the Communist Youth League Organization published and League branch of manual work, to promote the use of two manuals in the citys organizations at various levels. The county committee, directly under the group (work) is
14、 under the jurisdiction of grassroots League and group (total) using branch ratio shall not be less than 70%.Three, to further strengthen the groups leadership and team building(a) to strengthen the leagues leadership at all levels of construction. Continue to do a good job of municipal Party Commit
15、tee Organization Department on the strengthening of the Communist Youth League cadres management opinions implementation. To promote the group counties (autonomous counties, cities) Commission and city directly under the group (workers) appointed to carry out the Five team building activities. Impro
16、ve the League Association Department working mechanism. Conscientiously fulfill the duties of CO, combined with the city group directly under (the) Committee of the general election and the adjustment, actively jointly with the unit where the party organization department good group leadership selec
17、tion with the work. Do a good job in municipal Party committee assistant committee leadership and leading cadres of the annual assessment work, adhere to and improve the assistant secretary of the Communist Youth League talk system group To weave individual conversation and collective conversation,
18、to strengthen the committees of all levels, the Standing Committee of the Standing Committee, the establishment of a sound system of central group learning, the system of investigation and study, the system of important issues and the reporting system.(two) to strengthen the work of education and tr
19、aining of cadres to conscientiously implement the Central Committee. On the implementation of grassroots cadres training project and opinions on carrying out the mission municipal CYL Cadres training project implementation opinions, full implementation of the project of the City Youth League cadres
20、training education. Focus on the county grassroots cadres and workers focused on training, the new school system vocational training League cadres, for the Municipal Organization Department jointly held the third session of the Communist Youth League system training cadres in party. Focusing on the
21、construction of new socialist countryside, strengthening village cadres and rural construction team group member of the young team, the county organizations at various levels throughout the year is expected to train 100 00 rural grassroots cadres, plans to train 1000 village secretary of the village
22、 Party branch.(three) actively promote grassroots cadres election work. Under the unified leadership of the party organization, to strengthen grassroots organizations direct work, standardize the election work rules and procedures, in the designated candidate, open competition to democratically elec
23、ted branch secretary at the same time, actively and steadily the development of Township, streets and other grassroots organizations in the direct election of the pilot work, on the basis of summarizing the experience and gradually expand the scope of the pilot, and gradually formed a set of measure
24、s and cadres election system.(four) to strengthen the cadres testing exercise. To study the development of XX city from 2006 to 2008 cadres testing exercise planning. To select outstanding cadres to the central mission in Beijing, Shanghai, Guangzhou and other central organs and sending work in deve
25、loped areas. With the Central Committee the implementation of the western region and ethnic minorities cadres training plan . To carry out the eighth batch of municipal organs attachment cadre management, selection, training work. The outstanding cadres to start the National Development Bank XX bran
26、ch testing exercise.(five) to strengthen the group construction. The main position to play the role of Youth League cadre education and training as the city, in accordance with the requirements of post training, further curriculum scientifically and rationally, adopt arrangement menu course, basic t
27、heory includes group work, focus, hot and difficult issues, to enhance the content and practice; to strengthen the construction of teaching staff, the integration of teachers, establish a quality teacher training team, establish and implement course evaluation system; take delivery of training to th
28、e countryside, on-site training, and increase the rural grassroots cadres training efforts.Four, efforts to strengthen the work of young talent(a) to tenth XX young 54 medal in recognition of the publicity, and actively explore the XX youth service. 54 Medal of institutionalization, standardization
29、and socialization mechanism. Give full play to the XX award in recognition of 54 youth medal Association, Youth Award winner in the 54 chapter, investigation activities. Who won the Youth Service medal, dedication to the society to create conditions, build the stage. During the 54, named in recognit
30、ion of the tenth XX young 54 medal. The association of XX editing of young talent , the exchange of information and communication platform for the XX of outstanding young talents.(two) the establishment of municipal Party committee of young talent information database. In accordance with the feasibl
31、e, effective, classification management, implement step by step principle, the establishment of municipal Party committee of youth talent database; guiding organizations at various levels generally established the young talent database, construction of city, county (directly under the Communist Yout
32、h League), grassroots organizations three young talent information database the relevant information collection system, and gradually establish the citys young people, the Communist Youth League youth talent information network, provide information platform for young talent resource development.Five
33、, take effective measures to strengthen the mission management(a) to strengthen the mission management work. Strengthen the dues collection and management, continue to adhere to the dues collection regularly reporting system, the annual comprehensive award in recognition of the tour and the tour one
34、 vote veto system audit system. Do statistical work in the group. The group service award in recognition of the advanced units, standardization, promoting group management work institutionalized.(two) to strengthen the organization of research and information exchange efforts. Grassroots carry out r
35、esearch, efforts to form a number of theoretical results. Make full use of the network carrier, to explore the establishment of electronic group service system, promote the work of Communist Youth League information.Attachment 4:XX municipal Party Committee Propaganda Department of the Communist You
36、th League work pointsIn 2006, the Communist Youth League propaganda ideological work XX to Deng Xiaoping theory and the important thought of Three Represents as guidance, study and implement the partys sixteen and the spirit of the the fifth Plenary Session of the 16th CPC Central Committee implemen
37、tation of the eight plenary session of the two committee, the citys cultural work conference, the Propaganda Department of the meeting and the the fourth Plenary Session of the 15th CPC Central Committee permanent mission spirit, closely around 11th Five-Year XX the goal of full implementation of Sc
38、ientific Outlook on Development, emancipating the mind, seeking truth from facts, keep pace with the times, close to reality, close to life, close to the young, persevere grasp orientation, grasping deepening, grasping construction innovation, further improve the groups propaganda and ideological wo
39、rk ability, unity To guide the majority of members of the youth to achieve the 11th Five-Year planning tasks, the overall construction of a well-off society, building a socialist harmonious society to make new contributions.One, adhere to the Three Represents important thought and Scientific Outlook
40、 on Development education to guide the youth, to further strengthen the ideological and political education of youth(a) armed with youth science theory. Unremittingly with Deng Xiaoping theory and the important thought of Three Represents armed members of youth education, to promote the study and im
41、plement to expand the depth and breadth. To study and implement the important thought of Three Represents with the establishment and implementation of Scientific Outlook on Development combine with the implementation of the requirements of constructing socialist harmonious society with Scientific Ou
42、tlook on Development, carry out education as an important part of the theory of armed youth in the new period, strengthen the establishment and implementation of Scientific Outlook on Development education, educate and guide the youth to fully understand the great significance of establishment and i
43、mplementation of Scientific Outlook on Development, in-depth understanding of the Scientific Outlook on Development era back The king, the practice foundation, basic connotation, historical status, spirit and practice requirements, a profound understanding of Scientific Outlook on Development with M
44、arxism Leninism, Mao Zedong thought, inheriting and developing relationship between Deng Xiaoping theory and the important thought of Three Represents, to help young people establish and consciously practice Scientific Outlook on Development. Persist in learning, grasping the backbone, grasp the pra
45、ctice, grasp the opportunity. Catch club, effective way to grasp the network, with the group of cadres, young students and young backbone fronts as the focus, to promote the work of the armed youth theory to develop in depth, to help the youth continue to firm ideals and beliefs, to build a powerful
46、 spiritual pillar. To carry out the study and implementation of the partys sixteen session of the five Eight plenary session of the two plenary session of the Central Committee and the party spirit, to the citys Youth League members thinking into the spirit of the meeting, to achieve the goal of nat
47、ional consciousness and XX economic and social development in 11th Five-Year period. Contribute to help and guide the youth to a profound understanding of the significance and main task of building a socialist harmonious society, actively join the construction of socialist harmonious society.(two) t
48、o strengthen the ideological and moral construction of teenagers. Thoroughly implement the central spirit of the document No. 8, No. 16 and the program for Improving Civic Morality to minors and students as focus groups, to strengthen and improve the ideological and moral construction of minors and
49、the ideological and political education of college students. Make full use of the spirit and the spirit of the Three Gorges migrants Hongyan XX unique the use of educational resources, school, into the team, the league, to join the party, adult occasions, extensive Hongyan spirit generation theme education activities. Use of holidays and leisure
