md超载预压施工工艺.doc
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1、pension Gold 8*60 5, living allowance 13*568 four main 1, 2015, financial, education, design section, under the leadership of our accountants to study the countrys financial policies, laws, and familiarity with financial system actively studying accounting, master professional knowledge and master t
2、he accounting technique, adhere to principles, properly implement superior departments accounting requirements. 2, give full play to accounting initiative, careful budgeting annually, and do a year-end work on the budget no budget expenditure, budget expenditures, strictly control expenditures. Ofte
3、n communicating with school leaders reported financial position, and in terms of revenue ideas, ways to strictly implement the financial system, two lines of income and expenditure. 3, further standardize the schools financial management system, created the democratic financial management group, dem
4、ocratic financial group checks the school each semester accounts. Reporting annually to the schools financial income and expenses, so that all the teachers of school finances be aware. 4, with the school leadership greater control in school debt, does not give to the debt did not comply with procedu
5、res in the accounts. 5, various infrastructural projects to the school can do to teach . The poverty alleviation of poverty alleviation and training with the combination of the proposed by 2014. In the province, the city poverty alleviation and immigration office careful guidance and county Party co
6、mmittee and government of the correct leadership, the county seriously practice the scientific development view, and counties around the target, and comprehensively implement the Central Committee and the State Council on poverty alleviation immigration policy, adhere to the, strengthen infrastructu
7、re construction, accelerate the poor areas and immigration of education, health, culture and other public welfare undertakings development, the whole village advancement and the new rural construction, through the entire village advancement, poverty alleviation immigration, intellectual, social, ind
8、ustrial and other means, increasing the masses of poor and immigrant economic income a year, I do all the work staff Through joint efforts and struggle, and achieved excellent results, 2014 for 2666 million yuan project funds, and 2013 compared to increase by 60%, poverty alleviation and resettlemen
9、t work was named the citys third, Tan Lun Tan reservoir migrants synthetic immigration village as the citys economy to inspect a major bright spot, makes the contribution to the economic and social development in Qianshan. For 2020 together to achieve well-off society to make enormous contribution,
10、is now on the 2014 since the county to carry out the implementation of poverty alleviation and resettlement work are summarized as follows: A, poverty alleviation work 1, entire village advancement. Our countys agricultural population of 38 million people, poverty population of 4.9 million people, a
11、ccounting for 1 2.9%. The county, Twelfth Five Year Plan, will focus on poverty alleviation in the village of 14, since poor agricultural village has a total population of 2.55 million, poverty population 0.518 million people, accounting for 20%.2014 years, total planning project 20, 851 million yua
12、n of total investment, including 280 million yuan of poverty relief funds of central finance, county matching funds of 70 million yuan department support funds 3.76 million yuan, self超载预压施工工艺真空预压的特点1.1 真空预压法是利用大气来加固软地基,因此和堆载排水预压法相比,不许要大量的预压材料。1.2 真空预压法在施工时荷载无须分级施加,可以一次性快速施加到80Kpa以上而不会引起地基失稳,与堆载预压法相比
13、加载较快,可明显缩短工期。同时该法在卸载时只要抽气停止就可以了,因而施工起来简单、容易。1.3 在同等条件下真空预压法处理后地基比堆载排水法处理的地基密实度高,且加固均匀,平均沉降量要大1.4 在同等条件下,真空预压法加固地基时抗剪强度增长率比堆载排水法大。1.5 真空预压法的工程造价主要取决于真空泵的动力消耗。1.6 真空预压与堆栽预压相结合可以达到超载的目的,而不会产生填土超载预压的不利于稳定的弊端。2适用范围2.1 堆载材料缺乏,价格较高,工期较紧而电力供应不足地区。2.2 难以施加荷载的超载地基。2.3 临近危险边坡地带。3工艺原理真空预压法是排水固结法处理软土地基的有效方法之一,它是
14、利用专门的设备,通过抽真空在地基中产生负压,使土体空隙中的水分排出,从有效应力原理可知:空隙水排出,孔隙水压力减小后,有效应力就相应的增加,在压力差作用下,土体中的水分被排出,土体得到加固,土体强度得到提高。根据达西定律,土体中孔隙水的渗透速度与水力坡度正正比,增加水头差和减少排水距离L均可加速土体的排水固结。真空预压的加固机理是通过保持土体中的总应力不变,降低垂直排水通道中的孔隙水压力使之小于原有的孔隙水压力,即产生孔隙水压力,形成渗流需要的水力梯度;而堆载预压是通过施加外荷载使土体中的总应力增加,导致软土中的孔隙水压力增加并超过垂直排水通道中的孔隙水压力,即产生正的孔隙水压力,从而形成渗流
15、需要的水力梯度/两者联合应用,正负孔隙水压力压差增大,也就是增加了水头差,造成孔压消散更快,加固效果更好,真空联合堆载预压加固软基工艺原理见图34工艺流程及操作要点4.1 工艺流程见图4.11-平整场地;2-量测地面起始高程;3-埋设施工沉降观测板;4-铺设30砂砾垫层;5-打设排水板;6-铺设20cm砂砾垫层;7-铺设10cm砂垫层并敷设主管、滤管;8-埋设砂垫层中的真空度测头;9-挖密封沟;10-安置主管出膜装置;11-量测施工沉降量;12-铺土工布及土工膜;13-铺设10cm砂垫层;14-安装抽真空装置;15-回填密封沟;16-联接主管到抽真空装置;17-设置膜上沉降标;18-测沉降初值
16、;19-试抽真空;20-检查膜上及密封沟漏气情况;21-正式抽真空;22-施工监测开始;23-土方填筑开始;抽真空结束;(流程图见下页)4.2施工工艺下面结合杭州湾跨海大桥南接线工程第六合同段工程概况对真空联合堆载预压的施工工艺予以说明。工程概况:该工程位于浙江省慈溪市掌起镇,属于海积平原区。软土地基的特点是1亚粘土耕植土层厚1-2m。下伏1层淤泥质亚粘土软土层,土工试验指标低,变异性较大。主要的软土层为1:淤泥质亚粘土(Q42+m)灰色、灰褐色,饱和、流塑。层间夹亚粘土或亚砂土薄层,层厚约2-4cm。具有高含量、高孔隙比、高压缩性、高灵敏度等特征,工程地址条件很差。全合同段分布,埋深1-2m
17、,最厚达23.4m,不宜作为基础持力层。图4.1真空-堆载联合预压法施工工艺流程图软土地基处理设计标准:1、 路堤稳定控制标准:采用有效固结应力进行稳定性计算,不论在施工期还是运营期,其稳定系数K1.5;2、 路面设计使用年限(15年)内残余沉降满足下列要求:桥台与路堤相邻处0.10 m,涵洞或箱形通道处0.20 m,一般路段0.30 m。4.2.1水平排水系统施工 4.2.1.1清除表土,整平场地形成自路中心向两侧2%的横坡; 4.2.1.2砂的质量和规格必须符合设计要求和规范规定; 4.2.1.3砂垫层表面不得存留石块及其他尖利杂物并符合表4.2.1.3要求;表4.2.1.3 砂垫层施工要
18、求项次 检查项目 规定值或允许偏差 检查方法和频率1 砂垫层的厚度 不小于设计 每200 m检查4处2 砂垫层的宽度 不小于设计 每200 m检查4处3 反滤层的设置 符合设计要求 每200 m检查4处4 压实度 90 每200 m检查4处4.2.2垂直排水系统施工 4.2.2.1塑料排水板的施工工艺如下:移动插班机就位,调正套管垂直度,对准桩位。在空心套管中插穿入钢靴,再将排水板回插入套管咀中,拉紧排水板,使钢靴紧贴套管沉入土层,至设计要求深度; 以震动加压的方式将套管沉入土层,至设计要求深度; 拔出空心套管,由于土对钢靴及排水板的粘结力而使排水板留在土中; 留出排水板埋入砂垫层的长度约为3
19、0,将排水板减断,移动导管至下一桩位,继续下一根排水板施工。 4.2.2.2排水板施工注意事项 施工前根据设计要求打设深度及地质情况选用合适的插班机; 排水板在打设当中出现回带现象较严重时,除严格控制淤泥进入套管外,必要时可向管内适量注水,如回带超过0.5 m时应重新补打; 打设排水板时留在孔口的淤泥应及时清除,以防污染砂垫层; 打设排水板不应扭曲,滤膜不应破损或污染; 排水板接长时应拆开滤膜,对准芯班槽口,再包好滤膜,用钉固定,搭接长度不应小于0.2 m严禁浮放搭接; 排水板应露出第一层砂垫层15,弯倒埋入第一层砂垫层。 4.2.2.3塑料排水板施工要求应符合表4.2.2.3的规定表4.2.
20、2.3塑料排水板施工要求项次 检查项目 规定值或允许偏差 检查方法和频率1 板间距() 150 抽查2%2 板长 不小于设计 查施工记录3 竖直度 1.5 查施工记录 4.2.2.4排水板打设完毕并验收合格后应及时仔细地用砂料把打设时在每根塑料排水板周围形成的孔洞回填好,否则抽真空时这些孔洞附近的密封薄膜很容易造成漏气从而难以达到和维持要求要求的真空度;4.2.3.1抽真空系统施工4.2.3.1抽真空系统主要包括:主、滤管安装,主管出膜装置,抽真空设备安装;4.2.3.2一般每台真空泵担负软基处理面积为8001000,据此可根据软基处理总面积算得真空泵的数量,再根据真空泵的数量计算出主管间距,
21、滤管间距一般为68m。主滤管布置要求见图4.2.3.2。4.2.3.3滤管与滤管连接可在管头涂PVC 胶水,再将小管头塞入略大管头相连接。4.2.3.4主管与滤管连接由三通和四通构成,三通、四通与个管采用钢丝橡胶软管,要求钢丝橡胶软管套入真空管和三通、四通的长度10,并用12号铅丝绑扎,绑扎时注意沿线路横向不应过紧,达到不使沙砾进入真空管即可,并要求铅丝头向下,以防止其损坏密封膜。4.2.3.5 主管出膜采用在膜上挖洞,在膜外用专用塑料胶水粘贴双层密封膜堵漏进行处理,要求见图4.2.3.54.2.3.6 主管出膜后用橡胶软管接入止回阀,止回阀再与抽真空装置连接,其安装见图4.2.3.64.2.
22、3.7抽真空装置由水箱、射流喷嘴、真空吸管、污水泵组成,安装见图4.2.3.7,水箱安装在密封沟上,并应使其高度低于密封膜面高度图4.2.3.74.2.4密封系统施工 4.2.4.1密封系统施工包括密封膜,密封沟,土体深层密封,加固中地表开裂的密封。 4.2.4.2密封膜加工时,尺寸大小应考虑埋入密封沟的部分; 4.2.4.3密封膜铺设自一边开始,;两层一道顺序同时由近及远进行铺设; 4.2.4.4密封膜埋入密封沟时,注意膜不要被石头、草根、树根等戳破; 4.2.4.5密封沟回填好后,在沟中放水,水深控制在10左右,若密封沟有漏气,水面、会有漩涡。 4.2.4.6密封膜铺好后,进行试抽真空,检
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