摘要
福堂水电站位于四川省阿坝藏族羌族自治州汶川县境内的岷江河段上，电站为低闸引水式开发。正常蓄水位1268.0m，最大闸高31m，库容297.4万m~3，引水隧洞长19.57km，装机360MW。
福堂水电站闸坝建于深厚覆盖层基础上，基础主要存在五大覆盖层，总体属于多层复杂地基。由粗、细粒土相互迭置成层，层内不同高程上有透镜状砂层分布，均一性较差，地基可能出现不均一沉陷变形。地基中间隔存在第②和第④层两层浅灰黄色砂层，均系堰塞湖相沉积物，电站处于8°地震设防区，在7°、8°地震情况下第④层砂层均有液化的可能；第②层砂层均不液化，但在8°地震情况下砂土抗液化的安全系数不高。
文中以在建的福堂水电站闸基基础处理为重点，对深厚覆盖层基础处理进行研究、思索和探导，以期达到抛砖引玉的目的，并为待(在)建工程起到一定的参考借鉴作用。
本文着重对防渗型式等基础处理进行了研究，对于闸基防渗措施，研究了垂直防渗与水平铺盖防渗相结合的措施。混凝土防渗墙穿过透水性强的冲积层，置于相对隔水层内。通过计算，分析地基的变形情况，以便选择合理的结构型式和尺寸，确定施工进度和先后顺序。根据计算结果，选择较为合理的地基处理措施，以保证水闸的安全运用。
根据福堂电站工程设计的结构布置情况、地质参数及渗流计算成果，对闸室和挡水坝稳定、应力进行了计算，其抗滑稳定安全系
数及应力标准均满足规范的要求。
采用ANSYS结构分析软件，对闸坝结构和地基进行三维有限
元静力分析和动力响应分析。静力分析采用弹性和理想弹塑性材料
进行模拟，动力分析采用模态分析并结合动力反应谱法进行。分析
一计算结构及地基在竣工期、运行期和地震作用下变形和应力分布状
况，并初步判断闸坝基础卜伏砂层的动弧度及液化的可能性。
基于基础处理各种方案的比较、闸坝基础渗流的i}算结果、闸
坝基础沉降量的i一1算结果以及承载能力计算结果的综合分析，参考
借鉴其它〕_二程的成果和计算分析成果，提出了综合解决闸坝基础防
渗、抗液化和不均匀沉降等问题的处理方案，该方案在各种组合工
况下主要建筑物的稳定、应力均能满足规程规范要求。基础不均匀
沉降问题也能得到较好控制，防砂层液化问题也基本解决，在工程
完建后增加基础压重的情况下，覆盖层基础中砂层的渗透破坏坡降
也大大提高。使得基础地层内及其层间部分超出地质建议指标的渗
透坡降不致对砂层造成破坏性的渗透破坏，覆盖层地基的渗透稳定
得以满足要求。
Futang power station is located in the Minjiang River segment of Wenchuan Country of Sichuan Province. The power station is diversion type power station of low gate dam with a normal storage level of 1268.0 m, a highest gate dam level of 31 meters and a reservoir capacity of 2,974,000 cubic meters, the length of diversion tunnel of which is 19.57 kilometers, installed capacity is 360MW
Futang power station is constructed on the basis of deep and thick overburden, the foundation of which mainly consist of five overburdens which, in general, belong to multiple, complex foundation. The foundation are formed by the inter-layer of fine and crude earth, in the different level of the layer, are distributed lenticular sand, which result in the poor uniformity. The power station is situated in the area of 8° earthquake fortified zone, the fourth sand layer are probably liquefied and the second sand layer are not liquefied in the situation of 7°, 8° earthquake. However the security index of anti-liquefying of second sand is not very high in the situation of 8° earthquake.
In this paper, by focusing on the treatment of gate dam foundation of Futang power station under construction, and finally by the researches, contemplation and exploration made on the basic treatment of deep and thick overburden, we intent to use these results to offer some reference for the related projects.
Our researches are focused on the basic treatment as anti-seepage style and related problems, as regards the anti-seepage measures of
gate dam foundation, the combination measures of vertical anti-seepage and horizontal blanket anti- seepage are studied here. Concrete anti-seepage wall are penetrated through the alluvial layer with high water permeability and put in the relative impermeable layer. In order to chose the reasonable structure and size and determine the execution progress and order, it is necessary to first calculate the architecture and then analyze the deformation of foundation. According to these calculation results, proper measures are chosen to secure the proper operation of sluice.
According to the structure layout of Futang power station design, geological parameters and calculation results of seepage, the stability and stress of gate chamber and retaining dam are calculated, the security index and stress of anti-slide can can meet the requirement of criterion.
The structure of dam and foundation was analyzed in terms of 3-dimentional finite element static analysis and kinetic reaction analysis by ANSYS software. static analysis was analogued by elasticity and ideally elastic-plasticity material, while kinetic analysis was carried out by the combination of modal analysis and kinetic reaction analysis hierarchical method. By analyzing and calculating the structure and stress distribution status of foundation under time of completion, operating period and earthquake condition, the initial determination on the kinetic strength and liquefied possibility of underlying sand layer beneath the dam foundation are obtained.
On the basis of comparison of different plan, calculation results of seepage of dam foundation and the calculation results of gate dam foundation settlement value and the integrated analysis of the calculation results of load supporting capacity, with additional reference to other project, the resolutions to the anti-seepage,
anti-liquefaction and uneven sedimentation of foundation were put forward. The basic uneven settlement problem were controlled well, also the anti-liquefied problem of sand layer nearly was solved in this plan. When increasing the basic gravity after the project completion, the proportional lowering of seepage damage of sand in overburden foundation are greatly improved. which avoid the damage to the seepage of interlayer and inner layer of foundation, which is surpass the suggested standard, therefore the meet the seepage stability of overburden foundation can meet the requirement.
引文
①《渗流计算分析与控制》毛昶熙主编 水利电力出版社
②《电模拟试验与渗流研究》毛昶熙 水利出版社
③《水力学》吴持恭 高等教育出版社
④《水工设计手册》第15章 华尔水利学院主编
⑤《水力计算手册》武汉水利电力学院水力教研室编 水利电力出版社
⑥《水利水电施工技术规范汇编》水利部建设开发司 国防工业出版社
⑦《坝基防渗与灌浆技术》张景秀 水利电力出版社
⑧《水工建筑物设计手册》[苏]Β.Π涅德里格 北京勘测设计院译
⑨《水工建筑物》天津大学主编 水利电力出版社
⑩《土石坝地基混凝土防渗墙设计与计算》郑秀培 水利电力出版社
(11)《平原地区水闸设计参考手册》长江水利委员会 水利出版社
(12)《土坝安全与加固》牛运光 中国水利水电出版社
(13)《地基的震动液化与振冲加固法》曲镇洲 水利电力出版社
(14)《水闸手册》张世儒 夏维城 水利电力出版社
(15)《水闸设计》华东水利学院编 上海科学技术出版社
(16)《水闸设计规范》SL265-2001 水利部发布
(17)《水工建筑物抗震设计规范》DL5073-2000 国家经贸委发布
(18)《汶川福堂水电站工程场地地震安全性评价报告》四川省地震局工程地震研究所
(19)《水工渗流发展与坝工建设》毛昶熙 人民长江
(20)《闸坝地基渗流的近似计算方法》毛昶熙 周保中 水利水运科技情报
(21)《闸坝地基渗流计算的改进阻力系数法》毛昶熙 周保中 水利学报
(22)《土坝二向渗流的有限单元法计算与坝坡稳定分析》李祖贻 陈平 李定方 水利水运科学研究
(23)《无限深透水地基上不透水铺盖斜墙土坝渗流计算》周保中 水力发电
(24)《有垂直防渗的强透水地基均质土坝的渗流计算》郭发明 马秀辉 水利水运科学研究
(25)《悬挂式防渗墙对心墙土坝渗流量影响的初步研究》温丽林 水利水运科学研究
(26)《瀑布沟水电站钢筋混凝土面板堆石坝三维地震反应及覆盖层饱和砂透镜体液化分析》大连现工大学土木系水工教研室
(27)《映秀湾水电站安检综合报告》四川省电力公司大坝安全监察中心
(28)《太平驿水电站安检综合报告》国电公司大坝安全监察中心
(29)《南桠河三级原型观测资料分析报告》四川省电力公司大坝安全监察中心
(30)《福堂水电站首部枢纽调整设计报告》国电公司成都勘测设计研究院
(31)《福堂水电站可行性研究报告》国电公司成都勘测设计研究院
(32)《福堂水电站土工、岩石、材料力学试验报告》国电公司成都勘测设计研究院
(33)《福堂水电站可行性研究报告审查意见》国电司水规总院、四川省计委、建委
(34)《福堂水电站可行性研究报告咨询评估意见》国家计委、中国国际工程咨询公司
(35)《福堂水电站首部枢纽水工模型试验报告》国电公司成都勘测设计研究院
(36)《福堂水电站土工试验报告》国电公司成都勘测设计研究院
(37)《福堂水电站可研阶段闸坝基础处理及防渗设计报告》国电公司成都勘测设计研究院
(38)《映秀湾水电站闸坝基础渗流计算报告》国电公司成都勘测设计研究院
(39)《映秀湾水电站技施设计报告》国电公司成都勘测设计研究院
(40)《太平驿水电站闸坝基础渗流计算报告》国电公司成都勘测设计研究院
(41)《太平驿水电站技施设计报告》国电公司成都勘测设计研究院
(42)《混凝土防渗墙墙体材料及接头型式研究》电力部成都勘测设计研究院
(43)《福堂工程闸室稳定、应力、承载力计算书》国电公司成都勘测设计研究院
(44)《福堂工程挡水坝稳定、应力、承载力计算书》国电公司成都勘测设计研究院
(45)《深厚覆盖层取样技术》能源部、水利部成都勘测设计研究院
(46)《深厚覆盖层建坝研究论文集》水利电力部成都勘测设计研究院
(47)《福堂电站闸门荷载计算书》国电公司成都勘测设计研究院