筏板基础大体积混凝土降温施工

筏板基础大体积混凝土降温施工 筏板基础大体积混凝土浇筑降温施工 一、编制依据 《建筑工程施工质量验收统一》GB50300-2001 《建筑地基基础工程施工质量验收规范》GB50202-2002 《混凝土结构工程施工规范》GB50666-2011 《普通混凝土用砂质量标准及检验方法》JGJ52,92 《普通混凝土用碎石和卵石质量标准及检验方法》GJ53,92 《混凝土膨胀剂》GB23439-2009 《混凝土外加剂应用技术规范》GB50119,2003 《普通混凝土配合比设计规程》JGJ55,2011 《大体积混凝土施工规范》GB50496-2009 《高层建筑筏形及箱形基础技术规范》JGJ6-2011 二、工程概况 本工程3#主楼基础为筏板基础，板厚1.8m，属于大体积混凝土。筏板整体混凝土工程量约为3400m3 ，混凝土强度等级C30;挡水板和挡土墙砼为C30.P6。外加膨胀 抗裂防水剂。这种大体积混凝土底板施工具有水化热高、收缩量大、容易开裂等特点，故底板大体积混凝土浇筑应作为一个施工重点和难点认真对待。大体积混凝土施工重点主要是将温度应力产生的不利影响减少到最少，防止和降低裂缝的产生和发展。因此我项目部考虑采取如下施工措施。 三、混凝土配合比 考虑水泥水化热引起的温度应力和温度变形，在混凝土级配及施工superior to recruit full-time peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly carry out the volunteer service activities. Activities and pictures to timely submit command center and the Propaganda Department, convenient for internal and external publicity and communication. The Propaganda Department of the county bureau to do volunteer work instruction scheduling and coordination, and summarize and popularize advanced experience, to facilitate them to learn from each other, and timely organization of education and training, publicity and evaluation and award. At the same time, on a monthly basis volunteers safe construction and activities were informed online, organization construction included in the global performance appraisal, pay close attention to improving the management system, establish assessment incentives, the work of a serious and responsible, outstanding achievements Personnel to give recognition, and give some spiritual and material incentives, fully mobilize the enthusiasm of the majority of the volunteers, attach importance to create peace volunteer work, respect the peace volunteers, praise security volunteers behavior of the atmosphere and spare no effort to promote the smooth development of the construction of safety volunteers. Fourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work of the deployment and assigned the task learning, training and daily contact, to abide by the principle of confidentiality, and regulate their behavior, not the volunteers do things never let volunteers to do, resolutely put 过程中要注意如下问: 1、优先采用低水化热的矿渣硅酸盐水泥矿渣硅酸盐水泥比普通硅酸盐水泥水化热低，收缩小，导温效果好，对防止混凝土收缩裂缝有利。 2、骨料:粗细骨料不得含有有机杂质，应选用10m—30mm粒径的粗骨料且级配良好，含泥量不大于1%，细骨料的含泥量不大于3%，粗骨料采用连续级配，控制最佳空隙率以减少泌水。 3、掺加粉煤灰，以降低水化热提高抗渗性能，选用?级优质粉煤灰，要求主要性能指标应符合以下:细度:0.080MM方孔筛余量不大于8% 烧失量:不大于8% 三氧化硫:不大于3% . 4、混凝土采用微膨胀混凝土，混凝土内掺水泥用量8%-10%的膨胀剂，膨胀剂应为低碱型，同时减少水泥用量，降低水化热。掺加高效减水剂以及高强聚丙烯抗裂纤维。 5、施工期间要根据天气及材料等实际情况，及时调整砼水灰比，控制好砼的坍落度，并且应避免在雨天施工。 四、混凝土浇筑方案 4.1、混凝土施工 本工程主楼筏板尺寸较大，为防止冷缝出现，我们采用商品混凝土，两台汽车泵输送浇筑，施工时采取斜面分层、依次推进、整体浇筑的方法，使每次叠合层面的浇注间隔时间不大于2h，小于混凝土的终凝时间，施工过程中，不得因人员、机械等原因停止施工或在砼终凝前再次留施工缝。要求施工班组准备两组人员，结合现场具体浇筑实 behavior of the atmosphere and spare no effort to promote the smooth development of the construction of safety volunteers.teers rity of the volunteers, attach importance to create peace volunteer work, respect the peace volunteers, praise security volunnts Personnel to give recognition, and give some spiritual and material incentives, fully mobilize the enthusiasm of the majoievemen to improving the management system, establish assessment incentives, the work of a serious and responsible, outstanding achd activities were informed online, organization construction included in the global performance appraisal, pay close attentioion anof education and training, publicity and evaluation and award. At the same time, on a monthly basis volunteers safe constructtion, and summarize and popularize advanced experience, to facilitate them to learn from each other, and timely organization ordinaublicity and communication. The Propaganda Department of the county bureau to do volunteer work instruction scheduling and coActivities and pictures to timely submit command center and the Propaganda Department, convenient for internal and external pcarry out the volunteer service activities. time peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly-superior to recruit full 2late their behavior, not the volunteers do things never let volunteers to do, resolutely putdeployment and assigned the task learning, training and daily contact, to abide by the principle of confidentiality, and reguof the Fourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work 际情况调动，要求一定确保下料口混凝土能很好地覆盖下层已浇筑的混凝土，避免形成冷缝。 4.2混凝土的运输 本工程全部采用予拌商品混凝土，搅拌站确保8辆车供应混凝土，以保障混凝土的供应。 4.3现场平面布臵底板浇筑方量约3400m3，根据每小时浇筑量，采用2台混凝土汽车泵。 4.4混凝土浇筑前的准备工作 (1)对模板安装定位、钢筋绑扎、预埋件、预埋管线，预留孔洞进行交接检查并经监理及有关部门验收。 (2)为了避免施工时影响，对砼汽车泵提前进行试运行，确保汽车泵稳固，浇筑前汽车泵先使用砂浆润泵，在开始砼浇筑。 (3)填写砼搅拌通知单，通知搅拌站要浇筑砼的标号、配合比、搅拌方量。 (4)安排好混凝土浇筑时看护模板的工人，出现问题及时处理。 4.5混凝土的浇筑 (1)浇筑方法:由于泵送混凝土塌落度大，混凝土斜坡较长。故采取斜面分层浇筑，每层厚度为400mm，由西向东依次浇筑，一直达到厚度，每层浇筑间隔时间不小于2h。 (2)浇筑分段:在东西方向上分为一段，由东向西依次浇筑。 4.6混凝土的振捣 (1)在下料口，三个振捣手均匀分布在整个斜面，沿图示中小箭 construction of safety volunteers.f the ace volunteers, praise security volunteers behavior of the atmosphere and spare no effort to promote the smooth development oy mobilize the enthusiasm of the majority of the volunteers, attach importance to create peace volunteer work, respect the pe, fullious and responsible, outstanding achievements Personnel to give recognition, and give some spiritual and material incentivesormance appraisal, pay close attention to improving the management system, establish assessment incentives, the work of a serperf thly basis volunteers safe construction and activities were informed online, organization construction included in the globaleach other, and timely organization of education and training, publicity and evaluation and award. At the same time, on a mon n fromer work instruction scheduling and coordination, and summarize and popularize advanced experience, to facilitate them to learonvenient for internal and external publicity and communication. The Propaganda Department of the county bureau to do volunteent, carry out the volunteer service activities. Activities and pictures to timely submit command center and the Propaganda Departmme peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly cti-superior to recruit full of the deployment and assigned the task learning, training and daily contact, to abide by the pFourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work 3put rinciple of confidentiality, and regulate their behavior, not the volunteers do things never let volunteers to do, resolutely 头方向推进，确保不漏振，使新泵出的混凝土与上一斜面混凝土充分密实地结合。振捣应及时、到位，避免混凝土中石子流入坡底，发生离析现象。浇筑方法如(图一) (图一)注坡度:1:7,1:6但不陡于1:3. (2)混凝土采用机械振捣棒振捣。振捣棒的操作，要做到“快插慢拨”，上下抽动，均匀振捣，插点要均匀排列，插点采用并列式和交错式均可:插点间距为300,400mm ，插入到下层尚未初凝的混凝土中约50,100mm，振捣时应依次进行，不要跳跃式振捣，以防发生漏振。每一振点的振捣延续时间30s，使混凝土表面水分不再显著下沉、不出现气泡，表面泛出灰浆为止。为使混凝土振捣密实，每台混凝土泵出料口配备4台振捣棒(3台工作，1台备用)，分三道布臵。第一道布臵在出料点，使混凝土形成自然淌坡度，第二道布臵在坡脚处，确保混凝土下部密实，第三道布臵在斜面中部，在斜面上各点要严格控制振捣时间、移动距离和插入深度。振捣时插入式振动器振捣方向须与推进方向相反，沿斜面自下而上进行，逐渐上移。 (3)浇筑后的混凝土，必须在界限以前给予二次振捣，以排除混 behavior of the atmosphere and spare no effort to promote the smooth development of the construction of safety volunteers.teers rity of the volunteers, attach importance to create peace volunteer work, respect the peace volunteers, praise security volunnts Personnel to give recognition, and give some spiritual and material incentives, fully mobilize the enthusiasm of the majoievemen to improving the management system, establish assessment incentives, the work of a serious and responsible, outstanding achd activities were informed online, organization construction included in the global performance appraisal, pay close attentioion anof education and training, publicity and evaluation and award. At the same time, on a monthly basis volunteers safe constructtion, and summarize and popularize advanced experience, to facilitate them to learn from each other, and timely organization ordinaublicity and communication. The Propaganda Department of the county bureau to do volunteer work instruction scheduling and coActivities and pictures to timely submit command center and the Propaganda Department, convenient for internal and external pcarry out the volunteer service activities. time peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly-superior to recruit full 4late their behavior, not the volunteers do things never let volunteers to do, resolutely putdeployment and assigned the task learning, training and daily contact, to abide by the principle of confidentiality, and reguof the Fourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work 凝土因泌水在粗骨料、水平钢筋处形成的水分与空隙，提高混凝土与钢筋的握裹力，防止因混凝土沉落形成的裂缝，减少内部微裂，提高混凝土的抗压强度，从而提高抗裂性。 4.7泌水处理 (1)大体积混凝土的表现水泥浆较厚，且泌水现象严重，在控制水灰比前提下，应仔细处理。混凝土的体量及坍落度大，因此在施工中安排专人及时将出现的游离水排除到基槽里去，对较集中地带如电梯井、集水坑、浇筑终点设臵抽水机排除。 (2)预先在底板周围外模上留设泄水孔，及时处理混凝土浇筑中产生的泌水，免使粗骨料下沉，混凝土表面水泥砂浆过厚致使混凝土强度不均和产生收缩裂缝。 (3)浇捣混凝土时备用一台水泵，利用集水坑及时抽掉因振捣产生的泌水。对于表面泌水，当每层混凝土浇筑接近尾声时，应人为将水引向低洼边部，处缩为小水潭，然后用小水泵将水抽至附近排水井。 4.8混凝土表面处理在混凝土浇筑后4,8h内，将部分浮浆清掉，初步用长刮尺刮平，然后用木抹子搓平压实。在初凝以后，混凝土表现会出现龟裂，终凝要前进行二次抹压，以便将龟裂纹消除，注意宜晚不宜早。 4.9 搅拌采用冷水搅拌，控制砼的入模温度不超过25?。 4.10混凝土的养护 混凝土成型后，为保证水泥水化热作用正常进行，为砼硬化创造必要的湿度，温度条件，防止水份过早蒸发，及砼强度降低和出现收缩 construction of safety volunteers.f the ace volunteers, praise security volunteers behavior of the atmosphere and spare no effort to promote the smooth development oy mobilize the enthusiasm of the majority of the volunteers, attach importance to create peace volunteer work, respect the pe, fullious and responsible, outstanding achievements Personnel to give recognition, and give some spiritual and material incentivesormance appraisal, pay close attention to improving the management system, establish assessment incentives, the work of a serperf thly basis volunteers safe construction and activities were informed online, organization construction included in the globaleach other, and timely organization of education and training, publicity and evaluation and award. At the same time, on a mon n fromer work instruction scheduling and coordination, and summarize and popularize advanced experience, to facilitate them to learonvenient for internal and external publicity and communication. The Propaganda Department of the county bureau to do volunteent, carry out the volunteer service activities. Activities and pictures to timely submit command center and the Propaganda Departmme peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly cti-superior to recruit full 5put rinciple of confidentiality, and regulate their behavior, not the volunteers do things never let volunteers to do, resolutelyof the deployment and assigned the task learning, training and daily contact, to abide by the pFourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work 裂缝等现象，必须及时对砼进行养护。浇筑在12h后覆盖一层塑料薄膜，然后在塑料薄膜上覆盖一层阻燃草帘(根据需要增减)进行养护，草帘要覆盖严密，以保证砼内外温差不超过25?，防止内自温差过大，形成温度裂缝。养护过程设专人负责。拆除时混凝土温度与环境温差要小于20?，并在中午气温比较高时才可进行拆除。 五、降温措施 为控制好混凝土内部温度与表面温度之差不超过22,25?，施工中主要采取如下措施: 5.1、尽量降低混凝土入模浇筑温度，在规范允许之内，最大限度降低水泥用量，必要时用湿润草帘盖泵管。 5.2为防止混凝土表面散热过快，避免内、外温差大而产生裂缝，避免混凝土内部温度过大，和控制混凝土温度本工程采用内臵冷水循环水管与表面覆盖草帘的降温方法。 5.3混凝土温差计算及各降温工法: 筏板混凝土施工在六月份，当时大气平均气温(T0)取25?。入模温度(Tq)25?，下列式中t为混凝土内部达到最高温度的时间。混凝土内部最高温度按经验计算: Tmax=Wc/10+Tq+F/50=400/10+20+65/50=71.3? 混凝土表面温度:混凝土表面温度受外界气温、养护方法、结构厚度等的影响: 混凝土的虚厚度:h’=K.λ/β=0.666×2.33/3.5=0.44 5.3.1铺草帘 behavior of the atmosphere and spare no effort to promote the smooth development of the construction of safety volunteers.teers rity of the volunteers, attach importance to create peace volunteer work, respect the peace volunteers, praise security volunnts Personnel to give recognition, and give some spiritual and material incentives, fully mobilize the enthusiasm of the majoievemen to improving the management system, establish assessment incentives, the work of a serious and responsible, outstanding achd activities were informed online, organization construction included in the global performance appraisal, pay close attentioion anof education and training, publicity and evaluation and award. At the same time, on a monthly basis volunteers safe constructtion, and summarize and popularize advanced experience, to facilitate them to learn from each other, and timely organization ordinaublicity and communication. The Propaganda Department of the county bureau to do volunteer work instruction scheduling and coActivities and pictures to timely submit command center and the Propaganda Department, convenient for internal and external pcarry out the volunteer service activities. time peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly-superior to recruit full late their behavior, not the volunteers do things never let volunteers to do, resolutely putdeployment and assigned the task learning, training and daily contact, to abide by the principle of confidentiality, and reguof the Fourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work 6 混凝土终凝后，立即进行保温养护，保温养护时间根据测温控制，当混凝土表面温度与大气温度基本相同时(约4,5d)，撤掉保温养护，改为浇水养护。浇水养护不得少于14d;保温养护措施:先铺一层塑料布，上面铺一层草帘子或毛毡，根据温差来决定帘子或毛毡的增加量，草帘子或毛毡上部再增加一层塑料布。 以其导热系数λ取0.14;内铺外盖塑料薄膜，其导热系数λ取0.09，代入得β=3.5 (a)混凝土的计算厚度: H=h+2h’=1.5+2×0.44=2.38m (b)混凝土的表面温度: T1=TMAX-T0=66.3-20=46.3? T1—混凝土达到最高温度时，混凝土中心温度与外界气温之差 T= T0+4×h’×(H- h’)×T1/H2=25+4×0.44×(2.38-0.44) ×41.3/2.38*2.38=47.91? 结论:混凝土中心最高温度与表面温度之差 TMAX-T=66.3-47.91=18.39,25? 故满足要求，可以保证质量。 5.3.2方法二:蓄水法 蓄水深度计算如下: 1)砼控制温度延缓时间7d则x=7d×24h/d=168h 2)混凝土表面系数:M=F/V=[229+276]/1033=505/1033=0.491/M 其中:F—砼:四周面积和表面面积V—砼: construction of safety volunteers.f the ace volunteers, praise security volunteers behavior of the atmosphere and spare no effort to promote the smooth development oy mobilize the enthusiasm of the majority of the volunteers, attach importance to create peace volunteer work, respect the pe, fullious and responsible, outstanding achievements Personnel to give recognition, and give some spiritual and material incentivesormance appraisal, pay close attention to improving the management system, establish assessment incentives, the work of a serperf thly basis volunteers safe construction and activities were informed online, organization construction included in the globaleach other, and timely organization of education and training, publicity and evaluation and award. At the same time, on a mon n fromer work instruction scheduling and coordination, and summarize and popularize advanced experience, to facilitate them to learonvenient for internal and external publicity and communication. The Propaganda Department of the county bureau to do volunteent, carry out the volunteer service activities. Activities and pictures to timely submit command center and the Propaganda Departmme peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly cti-superior to recruit full 7put rinciple of confidentiality, and regulate their behavior, not the volunteers do things never let volunteers to do, resolutelyof the deployment and assigned the task learning, training and daily contact, to abide by the pFourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work 体积按温差:Tmax—Tb=250控制 β=1.3(蓄水法透水系数)水泥用量Mc=420kg Qt=188KJ/Kg〃K(低热水泥7d时水化热值)T0=300C(气温取值) R=[X〃M〃(Tmax—Tb)〃β]/(700 T0+0.28Mc〃Qt)=(168×0.49×25×1.3)/(700×20+0.28×420×188)=0.074KW 由上式求得表面热阻系数，则砼表面的蓄水深度为hw=R〃λwhw—砼表面的蓄水深度R—砼表面热阻系数λw—水导入系数 当温差250c时，则hw=0.074×0.58=0.043m=4.30cm 当温差Tmax—Tb=300c，则蓄水深度为 hw′=hw〃Tmax′/ Tb=4.3×30/25=5.16cm 当气温为Tmax—Tb=350c时，则蓄水深度为 hw〃=hw〃Tb′/ Tb=4.3×35/25=6.02cm 由以上计算，则蓄水深度大于7cm可以满足要求。 5.3.1内置(普通钢管)冷水循环管法 为了有效的控制混凝土的徐变作用和防止因温度应力所引起的表面裂缝和贯穿裂缝，对于混凝土拌合料的质量要求和混凝土芯体温度应力所产生的裂缝得到有效控制，并根据本地区温度条件下的施工与现场条件相结合的方式，采用预埋冷水循环水管的方式与铺盖草帘的相结合的方式控制和释放温度收缩应力从而达到控制裂缝的目的。 (1)材料选用:根据现场施工情况及要求，采用内置冷水循环水管降温，循环水管所采用材料为镀锌管，规格(Φ5.0cm×0.027cm)。 behavior of the atmosphere and spare no effort to promote the smooth development of the construction of safety volunteers.teers rity of the volunteers, attach importance to create peace volunteer work, respect the peace volunteers, praise security volunnts Personnel to give recognition, and give some spiritual and material incentives, fully mobilize the enthusiasm of the majoievemen to improving the management system, establish assessment incentives, the work of a serious and responsible, outstanding achd activities were informed online, organization construction included in the global performance appraisal, pay close attentioion anof education and training, publicity and evaluation and award. At the same time, on a monthly basis volunteers safe constructtion, and summarize and popularize advanced experience, to facilitate them to learn from each other, and timely organization ordinaublicity and communication. The Propaganda Department of the county bureau to do volunteer work instruction scheduling and coActivities and pictures to timely submit command center and the Propaganda Department, convenient for internal and external pcarry out the volunteer service activities. time peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly-superior to recruit full 8late their behavior, not the volunteers do things never let volunteers to do, resolutely putdeployment and assigned the task learning, training and daily contact, to abide by the principle of confidentiality, and reguof the Fourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work (2)薄钢管特点 a.现场使用材料方便快捷。 b.由于普通钢管与混凝土的咬合更加紧密，接触表面积大和散热更快等特点，降温效果显著。 c.材料采购方便，市场货源充足，成本低，缩短采购时间提高施工效率。 (3)内臵冷水循环水管工艺及现场布臵 a(预埋普通钢管循环水管，竖向和水平间距为900*1000mm，其中竖向距离底部900mm布置层钢管，水平方向距离基坑侧壁1000mm，按“U”字型布置水平间距1000mm，端头攻丝，并以弯管接头和直接接头对联，连接时应牢固，并缠好冷胶带防漏水。将普通钢管与钢筋固定牢固以防混凝土灌注捣固时影响造成失效。在普通钢管的进出水口各设置一道阀门，以控制进水的方向和流量。根据本工程现场施工情况，为避开电梯井故分两侧布置冷水循环水管，(如下图二): 进水口 出水口 水 集水坑 集水坑 口 普通钢管平面布置图 construction of safety volunteers.f the ace volunteers, praise security volunteers behavior of the atmosphere and spare no effort to promote the smooth development oy mobilize the enthusiasm of the majority of the volunteers, attach importance to create peace volunteer work, respect the pe, fullious and responsible, outstanding achievements Personnel to give recognition, and give some spiritual and material incentivesormance appraisal, pay close attention to improving the management system, establish assessment incentives, the work of a serperf thly basis volunteers safe construction and activities were informed online, organization construction included in the globaleach other, and timely organization of education and training, publicity and evaluation and award. At the same time, on a mon n fromer work instruction scheduling and coordination, and summarize and popularize advanced experience, to facilitate them to learonvenient for internal and external publicity and communication. The Propaganda Department of the county bureau to do volunteent, carry out the volunteer service activities. Activities and pictures to timely submit command center and the Propaganda Departmme peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly cti-superior to recruit full 9put rinciple of confidentiality, and regulate their behavior, not the volunteers do things never let volunteers to do, resolutelyof the deployment and assigned the task learning, training and daily contact, to abide by the pFourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work 普通钢管剖面图(图二) b(循环水采用地下水，循环系统布置一个容量为6 /h的水泵， 因管道会产生一定的水阻，取折减系数为80%，冷却水流量为V 4.，水的比热为CW 4.19J/kg;水的质量密度W 1.0t/;进、出水温差取t 30?。每小时冷却水带走的热量为:105J/h.据有关资料，采用冷却水管循环水冷却技术3d冷却水影响混凝土的体积约占总体积的50%，因此，3d每小时每立方米混您土被冷却水带走的热量Q为279.93J/h c(使用冷却水后混凝土绝热温度值 在使用冷却循环水管后，通过内部降温和表面混凝土蓄水养护， behavior of the atmosphere and spare no effort to promote the smooth development of the construction of safety volunteers.teers rity of the volunteers, attach importance to create peace volunteer work, respect the peace volunteers, praise security volunnts Personnel to give recognition, and give some spiritual and material incentives, fully mobilize the enthusiasm of the majoievemen to improving the management system, establish assessment incentives, the work of a serious and responsible, outstanding achd activities were informed online, organization construction included in the global performance appraisal, pay close attentioion anof education and training, publicity and evaluation and award. At the same time, on a monthly basis volunteers safe constructtion, and summarize and popularize advanced experience, to facilitate them to learn from each other, and timely organization ordinaublicity and communication. The Propaganda Department of the county bureau to do volunteer work instruction scheduling and coActivities and pictures to timely submit command center and the Propaganda Department, convenient for internal and external pcarry out the volunteer service activities. time peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly-superior to recruit full 10late their behavior, not the volunteers do things never let volunteers to do, resolutely putdeployment and assigned the task learning, training and daily contact, to abide by the principle of confidentiality, and reguof the Fourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work 可使混凝土的中心温度与气温控制在25?以内。 d(在混凝土浇灌完成12小时后方可采用冷水从进水口注水，出水口流出的水直接放入循环水水池内散热，同时根据昼夜温度变化增加和减少注水次数，控制好其温防止升降过大满足规范要求。施工时应在混凝土浇筑后12h往混凝土表面注水，并蓄水至比混凝土面高出10cm，同时进行循环水降温养护，养护期不小于15天。 e(施工工艺流程 施工准备?筏板底筋绑扎?筏板侧筋绑扎?铺设普通薄钢管?弯度，又使所测的温度数据稳定、准确、可靠。 (2)测温点的布置 a( 竖向点布臵:竖向测温点布臵，应能将混凝土竖向的温度分 布为原则，一般布臵上、中、下三个混凝土内部测温点 和一个混凝土表面上控制中的测温点。竖向测温点布臵，按 照顶表面温度、中心温度、底表面温度的检测要求进行布设 测温点A B C D E F G H I J K L 6000 6000 6000 6000 6000 6000 6000 6000 6470 construction of safety volunteers.f the ace volunteers, praise security volunteers behavior of the atmosphere and spare no effort to promote the smooth development oy mobilize the enthusiasm of the majority of the volunteers, attach importance to create peace volunteer work, respect the pe, fullious and responsible, outstanding achievements Personnel to give recognition, and give some spiritual and material incentivesormance appraisal, pay close attention to improving the management system, establish assessment incentives, the work of a serperf thly basis volunteers safe construction and activities were informed online, organization construction included in the globaleach other, and timely organization of education and training, publicity and evaluation and award. At the same time, on a mon n fromer work instruction scheduling and coordination, and summarize and popularize advanced experience, to facilitate them to learonvenient for internal and external publicity and communication. The Propaganda Department of the county bureau to do volunteent, carry out the volunteer service activities. Activities and pictures to timely submit command center and the Propaganda Departmme peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly cti-superior to recruit full 11put rinciple of confidentiality, and regulate their behavior, not the volunteers do things never let volunteers to do, resolutelyof the deployment and assigned the task learning, training and daily contact, to abide by the pFourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work (图三) 测温点平面布置图 平面测温点布臵市根据基坑外形而布置，在中轴线横线和斜线方 向均可作为各部位的代表，共布置6个点，上中下布置是把基础中各层次的混凝土内,温度差直接反映出来，以便在已做好的保温控制基础上更好地掌握调整和确保混凝土最终质量(图四)。 各组测温点剖面图(图四) 6.2测温时间 大体积混凝土浇筑后，必须进行监测，专人检测表面温度与结构 中心温度，测温时间不小于14d，在混凝土内部温度峰值来临前期( 72h前)每2h测一次;混凝土内部温度峰值来临后期(72h后)每 4h测一次，再后期6,8h测一次，同时应测大气温度。所有测温点均需编号，测温过程中如发现温差大于25?时，要采取有效措施，要覆盖保温等。当温差小于25?时，可停止测温，如测温结果与标准偏差较大，应继续测温监控。测温结果交技术负责人阅签，并作为对混凝土施工质量控制的依据，并及时做好记录填写温控记录表 behavior of the atmosphere and spare no effort to promote the smooth development of the construction of safety volunteers.teers rity of the volunteers, attach importance to create peace volunteer work, respect the peace volunteers, praise security volunnts Personnel to give recognition, and give some spiritual and material incentives, fully mobilize the enthusiasm of the majoievemen to improving the management system, establish assessment incentives, the work of a serious and responsible, outstanding achd activities were informed online, organization construction included in the global performance appraisal, pay close attentioion anof education and training, publicity and evaluation and award. At the same time, on a monthly basis volunteers safe constructtion, and summarize and popularize advanced experience, to facilitate them to learn from each other, and timely organization ordinaublicity and communication. The Propaganda Department of the county bureau to do volunteer work instruction scheduling and coActivities and pictures to timely submit command center and the Propaganda Department, convenient for internal and external pcarry out the volunteer service activities. time peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly-superior to recruit full Fourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work 12late their behavior, not the volunteers do things never let volunteers to do, resolutely putdeployment and assigned the task learning, training and daily contact, to abide by the principle of confidentiality, and reguof the (如下图表五)。 日期 次 筏板 筏板 筏板 最大 当日平测量人 数 下部 中部 上部 温差 均温度 签字 筏板大体积混凝土测温记录表 七、混凝土降温补救措施 (1)为了有效的控制混凝土的徐变作用和防止因温度应力所引起 的表面裂缝和贯穿裂缝，对于混凝土拌合料的质量要求和混凝土芯体 温度应力所产生的裂缝得到有效控制，采用埋〃设冷水循环水管与表 面覆盖草帘相结合的方式有效控制和释放温度收缩应力从而达到控 制裂缝的目的。根据其温度是否增加草帘，以及增加内臵冷水循环水 管的水流量，则其温度情况白天夜晚专人控制。 (2)如果内置冷水循环水管与表面覆盖草帘的降温方法实施后， 温度仍然高居不下，启用蓄水法，进行紧急 降温。 八、突发事件的处理 construction of safety volunteers.f the ace volunteers, praise security volunteers behavior of the atmosphere and spare no effort to promote the smooth development oy mobilize the enthusiasm of the majority of the volunteers, attach importance to create peace volunteer work, respect the pe, fullious and responsible, outstanding achievements Personnel to give recognition, and give some spiritual and material incentivesormance appraisal, pay close attention to improving the management system, establish assessment incentives, the work of a serperf thly basis volunteers safe construction and activities were informed online, organization construction included in the globaleach other, and timely organization of education and training, publicity and evaluation and award. At the same time, on a mon n fromer work instruction scheduling and coordination, and summarize and popularize advanced experience, to facilitate them to learonvenient for internal and external publicity and communication. The Propaganda Department of the county bureau to do volunteent, carry out the volunteer service activities. Activities and pictures to timely submit command center and the Propaganda Departmme peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly cti-superior to recruit full 13put rinciple of confidentiality, and regulate their behavior, not the volunteers do things never let volunteers to do, resolutelyof the deployment and assigned the task learning, training and daily contact, to abide by the pFourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work 对在混凝土浇筑过程中可能发生的影响混凝土连续浇筑的突 然事件，我们应做好充分的预防、准备工作: 1(针对在浇筑过程中可能出现的潜水泵损坏问题，施工前应做到每一种型号都有备用泵。 2(因整个筏板的混凝土浇筑时间较长，这期间天气又可能发生变化，故应做好充分的防雨工作。 3. 为防止因偶然事件引发施工现场全面停电造成混凝土无法连续浇筑的现象发生，施工前与建设单位协商好，做好备用电源工作。同时联系好商品砼。 4. 为防止施工期间发生振捣棒损坏而影响施工质量，施工前每一个料口均应配有一台备用的振捣棒。 九、施工注意事项 1(为保证施工顺利进行，不出现质量事故，施工前应周密计划，统一协调，使施工有条不紊地进行。 2(混凝土浇筑应注意使中部的混凝土略高于四周边缘的混凝土，以便使经振捣产生的泌水向四周排出，以减少混凝土表面产生的浮浆。 3(在整个浇筑期间，各工种都要设专人加强对钢筋、模板的看管，防止走动。 4(浇筑混凝土前，施工队放线人员应在钢筋上做好混凝土标高的控制标志。 5(混凝土表面二次磨压后应进行扫毛处理。 behavior of the atmosphere and spare no effort to promote the smooth development of the construction of safety volunteers.teers rity of the volunteers, attach importance to create peace volunteer work, respect the peace volunteers, praise security volunnts Personnel to give recognition, and give some spiritual and material incentives, fully mobilize the enthusiasm of the majoievemen to improving the management system, establish assessment incentives, the work of a serious and responsible, outstanding achd activities were informed online, organization construction included in the global performance appraisal, pay close attentioion anof education and training, publicity and evaluation and award. At the same time, on a monthly basis volunteers safe constructtion, and summarize and popularize advanced experience, to facilitate them to learn from each other, and timely organization ordinaublicity and communication. The Propaganda Department of the county bureau to do volunteer work instruction scheduling and coActivities and pictures to timely submit command center and the Propaganda Department, convenient for internal and external pcarry out the volunteer service activities. time peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly-superior to recruit full 14late their behavior, not the volunteers do things never let volunteers to do, resolutely putdeployment and assigned the task learning, training and daily contact, to abide by the principle of confidentiality, and reguof the Fourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work 6(为避免大体积混凝土在浇筑时出现冷缝，要求施工队派专人看管流淌在低洼处的混凝土，必要时插上小旗，已使其在初凝前得到及时的覆盖。 7.混凝土浇筑振动棒不准触及埋件和测温元件。 8.混凝土强度达到1.2N/m?之前不准踩踏。 十、环保和安全措施 在施工过程中要严格按照《安全生产法》、《建筑安全检查标 准》(JGJ59-99)等有关安全规程和规定执行，并采取如下措施: (1)、建立健全安全保证体系，建立以项目经理为首的安全责任制，并设臵专职安全员。 (2)、施工前，对施工人员进行安全技术交底，使所有人员熟悉所施工项目的安全情况。 (3)、严格执行安全操作规程，正确配臵和使用安全防护用品，使检查制度化，做到不违章作业和不违章指挥。 (4)根据施工组织设计或专项施工方案制定不同施工阶段的安全防护方案采取有效的安全防护措施报有关部门批准后认真实施，加强操作人员的安全教育，并作好以防意外的安全应急预案。 (5)、作好施工现场的围护和安全警示，禁止非工作人员进入施工区域。 (6)、服从统一调度,听从统一指挥。 (7)、做到工完料净场地清，搞好现场文明施工。 construction of safety volunteers.f the ace volunteers, praise security volunteers behavior of the atmosphere and spare no effort to promote the smooth development oy mobilize the enthusiasm of the majority of the volunteers, attach importance to create peace volunteer work, respect the pe, fullious and responsible, outstanding achievements Personnel to give recognition, and give some spiritual and material incentivesormance appraisal, pay close attention to improving the management system, establish assessment incentives, the work of a serperf thly basis volunteers safe construction and activities were informed online, organization construction included in the globaleach other, and timely organization of education and training, publicity and evaluation and award. At the same time, on a mon n fromer work instruction scheduling and coordination, and summarize and popularize advanced experience, to facilitate them to learonvenient for internal and external publicity and communication. The Propaganda Department of the county bureau to do volunteent, carry out the volunteer service activities. Activities and pictures to timely submit command center and the Propaganda Departmme peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly cti-superior to recruit full Fourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work 15put rinciple of confidentiality, and regulate their behavior, not the volunteers do things never let volunteers to do, resolutelyof the deployment and assigned the task learning, training and daily contact, to abide by the p behavior of the atmosphere and spare no effort to promote the smooth development of the construction of safety volunteers.teers rity of the volunteers, attach importance to create peace volunteer work, respect the peace volunteers, praise security volunnts Personnel to give recognition, and give some spiritual and material incentives, fully mobilize the enthusiasm of the majoievemen to improving the management system, establish assessment incentives, the work of a serious and responsible, outstanding achd activities were informed online, organization construction included in the global performance appraisal, pay close attentioion anof education and training, publicity and evaluation and award. At the same time, on a monthly basis volunteers safe constructtion, and summarize and popularize advanced experience, to facilitate them to learn from each other, and timely organization ordinaublicity and communication. The Propaganda Department of the county bureau to do volunteer work instruction scheduling and coActivities and pictures to timely submit command center and the Propaganda Department, convenient for internal and external pcarry out the volunteer service activities. time peace volunteers, and the County Bureau of Ping Anzhi May Township Peace volunteers integration and development, jointly-superior to recruit full 16late their behavior, not the volunteers do things never let volunteers to do, resolutely putdeployment and assigned the task learning, training and daily contact, to abide by the principle of confidentiality, and reguof the Fourth, insist on differentiated principle. Peace volunteers just the auxiliary power of public security organs, in the work