水电站大坝心墙土料冬季填筑施工注意事项及规范规定

水(shui)电(dian)站大坝的(de)(de)填(tian)筑(zhu)(zhu)主要参(can)照心(xin)墙土(tu)(tu)料(liao)的(de)(de)填(tian)筑(zhu)(zhu)速度而定，由于(yu)土(tu)(tu)料(liao)在气温(wen)出(chu)现负温(wen)度时，会出(chu)现冻(dong)土(tu)(tu)情况，因此施(shi)(shi)工(gong)(gong)规范(fan)规定，当大气温(wen)度低于(yu)0℃时，应停止(zhi)心(xin)墙土(tu)(tu)料(liao)施(shi)(shi)工(gong)(gong)并采(cai)取有(you)效的(de)(de)覆(fu)盖(gai)保温(wen)措施(shi)(shi)，保温(wen)后可防止(zhi)仓(cang)面(mian)已(yi)填(tian)筑(zhu)(zhu)的(de)(de)心(xin)墙土(tu)(tu)料(liao)出(chu)现冻(dong)土(tu)(tu)现象(xiang)。故负温(wen)时段将(jiang)直接(jie)影(ying)响到大坝心(xin)墙土(tu)(tu)料(liao)填(tian)筑(zhu)(zhu)工(gong)(gong)期，影(ying)响大坝填(tian)筑(zhu)(zhu)的(de)(de)整体工(gong)(gong)期。目前已(yi)经修建(jian)的(de)(de)或在建(jian)的(de)(de)土(tu)(tu)石坝工(gong)(gong)程在冬(dong)季(ji)低温(wen)时段一般采(cai)用“干土(tu)(tu)覆(fu)盖(gai)”或“季(ji)节性停工(gong)(gong)”两种施(shi)(shi)工(gong)(gong)方法(fa)，待气温(wen)回升后，再开始施(shi)(shi)工(gong)(gong)。

但采用这两(liang)种(zhong)方法(fa)的(de)施(shi)工(gong)质量不易(yi)得到(dao)(dao)控制(zhi)，同(tong)时会一(yi)定程(cheng)度上造成施(shi)工(gong)成本增加、施(shi)工(gong)设备(bei)闲置(zhi)、填(tian)筑强(qiang)度大(da)(da)幅降低，影响(xiang)工(gong)期。两(liang)河口(kou)水电(dian)站及(ji)双江口(kou)水电(dian)站均处于高海(hai)拔、高寒地(di)区，冬季气温比较低，修(xiu)建(jian)300ｍ级砾石土料心墙(qiang)坝(ba)的(de)施(shi)工(gong)质量和进度也将会受到(dao)(dao)影响(xiang)。同(tong)时，在出现负温期间(jian)，会导致大(da)(da)量资源闲置(zhi)，经济损失十分巨大(da)(da)。为解决常(chang)规(gui)施(shi)工(gong)方法(fa)存(cun)在的(de)问(wen)题，项目部结合现场实际(ji)(ji)的(de)施(shi)工(gong)情(qing)况研制(zhi)了一(yi)种(zhong)可满足工(gong)程(cheng)实际(ji)(ji)需要的(de)“三布(bu)两(liang)膜”保(bao)温材料。但土工(gong)膜生产厂家(jia)未研究(jiu)相应的(de)收(shou)放机械装备(bei)，目前(qian)只能人工(gong)进行土工(gong)膜收(shou)放施(shi)工(gong)，需要投(tou)入大(da)(da)量的(de)施(shi)工(gong)人员(yuan)和机械设备(bei)，导致填(tian)筑强(qiang)度和资源投(tou)入不匹(pi)配。

水电站大坝心墙(qiang)土(tu)(tu)(tu)料冬(dong)季填筑施(shi)工(gong)(gong)采用(yong)“三布(bu)两膜(mo)(mo)(mo)(mo)(mo)(mo)”保(bao)(bao)温(wen)(wen)(wen)材料进(jin)行土(tu)(tu)(tu)料覆盖保(bao)(bao)温(wen)(wen)(wen)，施(shi)工(gong)(gong)时(shi)(shi)(shi)(shi)(shi)段(duan)随现场的(de)(de)气温(wen)(wen)(wen)而定，温(wen)(wen)(wen)度高(gao)于0℃时(shi)(shi)(shi)(shi)(shi)恢复施(shi)工(gong)(gong)，低于0℃时(shi)(shi)(shi)(shi)(shi)停止(zhi)施(shi)工(gong)(gong)。目(mu)前心墙(qiang)填筑面积约7500㎡，采用(yong)常(chang)规的(de)(de)铲车配(pei)合人(ren)工(gong)(gong)收放(fang)土(tu)(tu)(tu)工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)(mo)，每平方米土(tu)(tu)(tu)工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)(mo)质量约为(wei)(wei)1kg左右，每块土(tu)(tu)(tu)工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)(mo)被裁剪的(de)(de)尺寸为(wei)(wei)20ｍ×6ｍ。收揭土(tu)(tu)(tu)工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)(mo)时(shi)(shi)(shi)(shi)(shi)需25个(ge)人(ren)和2台(tai)装载机配(pei)合，3h完成土(tu)(tu)(tu)工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)(mo)收揭工(gong)(gong)作。铺(pu)设(she)土(tu)(tu)(tu)工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)(mo)时(shi)(shi)(shi)(shi)(shi)需30个(ge)人(ren)和1台(tai)装载机，铺(pu)设(she)土(tu)(tu)(tu)工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)(mo)的(de)(de)时(shi)(shi)(shi)(shi)(shi)间为(wei)(wei)3.6h。但每天(tian)有(you)限的(de)(de)土(tu)(tu)(tu)料施(shi)工(gong)(gong)时(shi)(shi)(shi)(shi)(shi)间为(wei)(wei)10h左右，故为(wei)(wei)了(le)能(neng)最(zui)大化(hua)地(di)利用(yong)正温(wen)(wen)(wen)下土(tu)(tu)(tu)料的(de)(de)施(shi)工(gong)(gong)时(shi)(shi)(shi)(shi)(shi)间，实际(ji)施(shi)工(gong)(gong)时(shi)(shi)(shi)(shi)(shi)存(cun)在收揭土(tu)(tu)(tu)工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)(mo)时(shi)(shi)(shi)(shi)(shi)间提前及铺(pu)设(she)土(tu)(tu)(tu)工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)(mo)时(shi)(shi)(shi)(shi)(shi)间推后的(de)(de)情况，导(dao)(dao)致(zhi)外界气温(wen)(wen)(wen)在低于0℃时(shi)(shi)(shi)(shi)(shi)，土(tu)(tu)(tu)料未覆盖，土(tu)(tu)(tu)料保(bao)(bao)温(wen)(wen)(wen)未受(shou)到保(bao)(bao)障。同时(shi)(shi)(shi)(shi)(shi)采用(yong)铲车配(pei)合搬运对土(tu)(tu)(tu)工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)(mo)的(de)(de)破坏(huai)较(jiao)大，导(dao)(dao)致(zhi)重复利用(yong)率(lv)较(jiao)低，并(bing)且每块土(tu)(tu)(tu)工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)(mo)尺寸较(jiao)小(xiao)，整体(ti)的(de)(de)保(bao)(bao)温(wen)(wen)(wen)效(xiao)果(guo)较(jiao)低，需要(yao)消(xiao)耗大量人(ren)工(gong)(gong)，劳动强度大、时(shi)(shi)(shi)(shi)(shi)间长、费用(yong)高(gao)，极易浪费每天(tian)有(you)限的(de)(de)正温(wen)(wen)(wen)施(shi)工(gong)(gong)时(shi)(shi)(shi)(shi)(shi)段(duan)，无法(fa)满足快(kuai)速流水作业要(yao)求。为(wei)(wei)了(le)解决上述土(tu)(tu)(tu)工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)(mo)快(kuai)速收放(fang)问题，项(xiang)目(mu)部使用(yong)了(le)自主研发的(de)(de)“土(tu)(tu)(tu)工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)(mo)快(kuai)速收放(fang)机”。