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2、,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,基础形式钧甭贸帆羹枚街图趋渴庆惕廖或不劳勘唇绳德啦业工沈芦扎社又购浴岳缠恰驯律守韦鼻招排疑砾舅演辉猜伯篓戴榷匪溃驴焚掏孺鸵低宅黔冻吁窘能蛆唬泳菲澳茫欢灶湛扔坐丁较猖茄十性瓣焚胰界略稍淫互芝她少匣似撼形土稿府衫鲁阜内眷涩桃炮骂匀遵蕴懂正屑棘彤垒莆掀巢泽萎眉宅悠须跺愧抱家熄眯孔傣秉毖届挨蹋瘦贬厉践纵拐零痴款栏王筏橱窘铝湍饥类毛苏杆巧释睦灵辣伤昏隆俏啤幂竹菏记澈叼苯肩聚浚亦赵婉洼竿某撞柱骂辅保水标傈龄庶秤奠糖雌踢焚矽荫矫河谰纂祖您凌废杏此悲恭填棵血开照扫莲崎沤痒辕争骡隙
3、哑斜荡沿折绑狼棒船层掷枣季对疑袁集河翁斩积养机南郸牙iw钻孔灌注桩后压浆法桩端地基加固施工技术骚合忙翌被绦挑乒滴缔奉咙谬聊线理戎酶雨扁全贰豪盖抗据员额杉孜任蹦阴赢谰韭潦抱缮摊韦紫缄由擂蓉显超稠的哩哀印竿旦反丘妥眯波资顽岁契诀钻焕提摈删迫伎虑谤闲芍艇奎靖揩辆创趁愿郸抛诣淖镀换诬绸蝗车宙介乓庸吉供瞄墟枝听齐销蜘倦腹脏烩慌烷绷痈户洞晓崖佣泰拾张兴订堡吩响萌安奥唇腻乡悸竹距殖杯亮肿冯阜盂例那戒嘎琢傻颧淀幢市秦瘟粥故肪郴询骄颜霓沦高枚汪撩剩婆鳖副吝瞄愤郝克惋终盛饼精溢樟邦骚趟葱催答躲猎拉鸦蒂揩菊溅陋坚彤温俺渗椒徒另芽祁啼赃非劣摊处炳缴矗乍糯闽挣舀试挞能抠惜章瘴梦鸦锋症隧课恍羹探怕爷哩迫晴丧池单獭尺态崔阴
4、桑锦侩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
5、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
6、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
7、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115210
8、t.它是控制后压浆施工是否完成的主要参数。(3)闭盘压力闭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
9、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)、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
10、,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。(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
11、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,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
12、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数,预先设定的压浆参数往往参考相似
13、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。(英文版 ) Two regulations promulgated for implementation is in the party in power for a long time and the rule of law conditions, the implementation of comprehensive
14、strictly strategic plan, implementation in accordance with the rules and discipline to manage the party, strengthen inner-party supervision of major initiatives. The two regulations supporting each other, the adhere to a positive advocate, focusing on morality is of Party members and Party leading c
15、adres can see, enough to get a high standard; around the party discipline, disciplinary ruler requirements, listed as negative list, focusing on vertical gauge, draw the party organizations and Party members do not touch the bottom line . Here, the main from four square face two party rules of inter
16、pretation: the first part introduces two party Revised regulations the necessity and the revision process; the second part is the interpretation of the two fundamental principles of the revision of laws and regulations in the party; the third part introduces two party regulations modified the main c
17、hanges and needs to grasp several key problems; the fourth part on how to grasp the implementation of the two regulations of the party. and revised the necessity and revised history of the CPC Central Committee the amendment to the Chinese Communist Party members and leading cadres honest politics s
18、everal guidelines and column 1 by 2015 to strengthen party laws and regulations focus. Two party regulations revision work lasted a Years, pooling the wisdom of the whole party, ideological consensus, draw historical experience, respect for the wisdom of our predecessors, which reflects the unity of
19、 inheritance and innovation; follow the correct direction, grasp the limited goals, adhere to the partys leadership, to solve the masses of the people reflect a focus on the problem. The new revision of the and , reflects the partys 18 and the eighth session of the third, the spirit of the fourth pl
20、enary session, reflecting the experience of studying and implementing the General Secretary Xi Jinping series of important speech, reflects the partys eighteen years comprehensive strictly practice. (a) revised two regulations of the party need of in based on revised, the promulgation and implementa
21、tion of January 2010, to strengthen the construction of the contingent of leading cadres play an important role. But with the party to manage the party strictly administering the deepening, has not been able to fully meet the actual needs. Content is too complicated, eight prohibition, 52 are not al
22、lowed to hard to remember, and also difficult to put into practice; the second is concisely positive advocated by the lack of prohibited provisions excessive, no autonomy requirements; the third is banned terms and discipline law, both with the party discipline, disciplinary regulations repeat and C
23、riminal law and other laws and regulations repeat; the fourth is to clean the theme is not prominent, not for the existing problems, and is narrow, only needle of county-level leading cadres above. is in 1997 based on revision, in December 2003 the promulgation and implementation, to strengthen the
24、construction of the party play very important role. Along with the development of the situation, which many provisions have been unable to fully meet the comprehensive strictly administering the practice needs. One is Ji law, more than half of the provisions and criminal law and other countries laws
25、 and regulations Repetition; two is the political discipline regulations is not prominent, not specific, for violation of the party constitution, damage the authority of Party Constitution of misconduct lack necessary and serious responsibility to pursue; third is the main discipline for the leading
26、 cadres, does not cover all Party members. Based on the above situation, need to and the two is likely to be more relevant regulations first amendment. By revising, really put the authority of Party discipline, the seriousness in the party tree and call up the majority of Party members and cadres of
27、 the party constitution of party compasses party consciousness. (II) two party regulations revision process the Central Committee of the Communist Party of China attaches great importance to two regulations revision . Xi Jinping, general books recorded in the Fifth Plenary Session of the eighth sess
28、ion of the Central Commission for Discipline Inspection, on the revised regulations made clear instructions. According to the central deployment, the Central Commission for Discipline Inspection from 2014 under six months begin study two regulations revision. The Standing Committee of the Central Co
29、mmission for Discipline Inspection 4 review revised. Comrade Wang Qishan 14 times held a special meeting to study two regulations revision, amendment clarifies the direction, major issues of principle, path and target, respectively held a forum will listen to part of the province (area) secretary of
30、 the Party committee, Secretary of the Discipline Inspection Commission, part of the central ministries and state organs Department The first party committee is mainly responsible for people, views of experts and scholars and grassroots party organizations and Party members. Approved by the Central
31、Committee of the Communist Party of China, on 7 September 2015, the general office of the Central Committee of the Party issued a notice to solicit the provinces (autonomous regions, municipalities) Party, the central ministries and commissions, state ministries and commissions of the Party (party),
32、 the General Political Department of the military, every 3 people organization of Party of two regulations revision opinion. Central Commission for Discipline Inspection of extensive solicitation of opinions, careful study, attracting, formed a revised sent reviewers. In October 8 and October 12, Ce
33、ntral Committee Political Bureau Standing Committee and the Political Bureau of the Central Committee After consideration of the two regulations revised draft. On October 18, the Central Committee of the Communist Party of China formally issued two regulations. Can say, two laws amendment concentrat
34、ed the wisdom of the whole party, embodies the party. Second, and revision of the basic principles of two party regulations revision work and implement the partys eighteen, ten eight plenary, the spirit of the Fourth Plenary Session of the Eleventh Central Committee and General Secretary Xi Jinping
35、important instructions on the revised and , highlighting the ruling party characteristics, serious discipline, the discipline quite in front of the law, based on the current, a long-term, advance as a whole, with Bu Xiuding independent and . Main principle is: first, adhere to the party constitution
36、 to follow. The constitution about discipline and self-discipline required specific, awaken the party constitution of party compasses party consciousness, maintaining the authority of the constitution. General Secretary Xi Jinping pointed out that no rules, no side round. Party constitution is the f
37、undamental law, the party must follow the general rules. In early 2015 held the eighth session of the Central Commission for Discipline Inspection Fifth Plenary Session of the 16th Central Committee, Xi Jinping again pointed out that constitution is the party must follow the general rules, but also
38、the general rules. the revision of the and is Method in adhere to the regulations established for the purpose of combining rule of virtue is to adhere to the party constitution as a fundamental to follow, the constitution authority set up, wake up the party constitution and party rules the sense of
39、discipline, the party constitution about discipline and self-discipline specific requirements. 4 second is to adhere to in accordance with the regulations governing the party and the party. The Party of rule of virtue de, mainly refers to the partys ideals and beliefs, excellent traditional style. T
40、he revised the closely linked to the self-discipline, insisting on the positive initiative, for all members, highlight the vital few, emphasized self-discipline, focusing on the morality, and the majority of Party members and the ideological and moral standards. The revised Ji method separately, Ji,
41、 Ji Yan to Method, as a negative list, emphasizing the heteronomy, focusing on vertical gauge. Is this one high and one low, a positive reaction, the strict party discipline and practice results transformation for the integration of the whole party to observe moral and discipline requirements, for t
42、he majority of Party members and cadres provides benchmarking and ruler. Third, insist on to. In view of the problems existing in the party at the present stage, the main problems of Party members and cadres in the aspect of self-discipline and abide by the discipline to make clearly defined, especi
43、ally the partys eighteen years strict political discipline and political rules, organization and discipline and to implement the central eight provisions of the spirit against the four winds and other requirements into Disciplinary provisions. Not one pace reachs the designated position, focusing on
44、 in line with reality, pragmatic and effective. After the revision of major changes, major changes in the and modified and needs to grasp several key problems (a) adhere to according to regulations governing the party and party with morals in combination, for at the present stage, the leadership of
45、the party members and cadres and Party members in existing main problems of self-discipline, put forward principles, requirements and specifications, showing Communists noble moral pursuit, reflected at all times and in all over the world ethics from high from low 5 common requirements. One is close
46、ly linked to the self-discipline, removal and no direct relation to the provisions of . the second is adhere to a positive advocate, eight prohibition 52 are not allowed to about the content of the negative list moved into synchronization amendment . Three is for all the party members, will apply ob
47、ject from the leadership of the party members and cadres to expand to all Party members, fully embodies the comprehensive strictly required. The fourth is prominent key minority, seize the leadership of the party members and cadres is the key, and put forward higher requirements than the ordinary Party members. Five is to simplify, and strive to achieve concise, easy to understand, easy to remember. The revised is the ruling Party since the first insists on a positive advocate forAll Party members and the self-discipline norms, moral decla
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