围堰施工工艺要点

1.开始冲灌

堰体(ti)施工开始时，应预(yu)先进(jin)行(xing)围(wei)堰的冲灌作(zuo)业。作(zuo)业期(qi)间应将外(wai)江两侧位(wei)置的石(shi)堤清(qing)除(chu)，并(bing)岸坡(po)位(wei)置、堰体(ti)位(wei)置连接处(chu)进(jin)行(xing)处(chu)理(li)(li)。该(gai)区域存在的石(shi)块、堆积物需(xu)要预(yu)先挖除(chu)清(qing)理(li)(li)干净(jing)，围(wei)堰基(ji)底位(wei)置也应做好清(qing)理(li)(li)工作(zuo)。由于场地内存在深坑，使用刨海填砂的施工工艺(yi)，控制河床深坑标高为-4m。

2.土工格栅铺设

土(tu)工(gong)格栅(zha)铺设施工(gong)作(zuo)业与(yu)填(tian)砂(sha)作(zuo)业同步进行，在(zai)(zai)填(tian)砂(sha)达到预(yu)(yu)定(ding)(ding)的(de)(de)高度之后，进行整(zheng)平处理(li)，确保(bao)其平整(zheng)度满足要(yao)求(qiu)。同时(shi)，在(zai)(zai)外(wai)江的(de)(de)低潮位(wei)(wei)时(shi)段(duan)，则使用钢(gang)管、抛沙袋固定(ding)(ding)，将土(tu)工(gong)格栅(zha)安置在(zai)(zai)砂(sha)层(ceng)上(shang)(shang)。在(zai)(zai)整(zheng)个施工(gong)过程中，需要(yao)严(yan)格控(kong)制抛沙、整(zheng)平、固定(ding)(ding)的(de)(de)工(gong)艺(yi)，在(zai)(zai)确定(ding)(ding)具体(ti)位(wei)(wei)置基础上(shang)(shang)，装船将其运输到特(te)定(ding)(ding)的(de)(de)施工(gong)区(qu)域(yu)，并保(bao)持抛沙船在(zai)(zai)预(yu)(yu)先定(ding)(ding)位(wei)(wei)的(de)(de)位(wei)(wei)置，采(cai)用定(ding)(ding)点、定(ding)(ding)量(liang)抛砂(sha)的(de)(de)施工(gong)工(gong)艺(yi)，完成抛砂(sha)后续进场验收(shou)，并铺设土(tu)工(gong)格栅(zha)，定(ding)(ding)位(wei)(wei)准确后驳移至下(xia)一区(qu)域(yu)。

3.膜袋固定

土(tu)工(gong)(gong)格(ge)(ge)栅铺设(she)(she)固(gu)(gu)定(ding)完(wan)成后(hou)，应(ying)进行(xing)膜(mo)袋(dai)(dai)的(de)定(ding)位(wei)和固(gu)(gu)定(ding)，底部膜(mo)袋(dai)(dai)铺设(she)(she)按照顺水流(liu)方(fang)向，其(qi)(qi)余则采用(yong)垂直铺设(she)(she)的(de)方(fang)式，分层铺筑(zhu)到测量的(de)高程为(wei)止。膜(mo)袋(dai)(dai)布(bu)设(she)(she)需要(yao)严格(ge)(ge)控制避免(mian)误差的(de)产(chan)生(sheng)(sheng)，使用(yong)固(gu)(gu)定(ding)性能(neng)较好的(de)钢管定(ding)位(wei)，避免(mian)水流(liu)对固(gu)(gu)定(ding)位(wei)置产(chan)生(sheng)(sheng)影响。放样(yang)测量期间，确(que)定(ding)袋(dai)(dai)子(zi)(zi)的(de)边缘位(wei)置，袋(dai)(dai)子(zi)(zi)耳(er)环位(wei)置用(yong)于插(cha)入钢管，将其(qi)(qi)平面铺设(she)(she)到水面上，其(qi)(qi)间需要(yao)严格(ge)(ge)控制，避免(mian)袋(dai)(dai)子(zi)(zi)发生(sheng)(sheng)位(wei)移现象，同时需要(yao)严格(ge)(ge)对应(ying)袋(dai)(dai)子(zi)(zi)的(de)规格(ge)(ge)和型号。底层膜(mo)袋(dai)(dai)施(shi)工(gong)(gong)具有隐(yin)蔽性的(de)特点，因此，需要(yao)将其(qi)(qi)弄(nong)到水面上，可(ke)利(li)用(yong)泡沫等具有漂浮功能(neng)的(de)物(wu)体，带动袋(dai)(dai)子(zi)(zi)到水面上，为(wei)后(hou)续的(de)充灌施(shi)工(gong)(gong)创造条(tiao)件，便于寻找(zhao)充灌口位(wei)置。

4.膜袋填充

膜(mo)(mo)(mo)(mo)袋(dai)填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)是围堰(yan)施(shi)工(gong)(gong)的(de)(de)(de)(de)关键(jian)，对(dui)(dui)堰(yan)体(ti)(ti)结(jie)构(gou)的(de)(de)(de)(de)质(zhi)量(liang)会(hui)产(chan)(chan)生巨大的(de)(de)(de)(de)影(ying)响。因此，膜(mo)(mo)(mo)(mo)袋(dai)充(chong)灌(guan)(guan)施(shi)工(gong)(gong)应(ying)严(yan)格控(kong)制(zhi)(zhi)工(gong)(gong)艺参(can)数(shu)，保(bao)障填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)的(de)(de)(de)(de)平(ping)整(zheng)度(du)(du)、饱(bao)和(he)度(du)(du)。填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)使用(yong)(yong)泵(beng)砂(sha)(sha)船进(jin)行，充(chong)填(tian)(tian)(tian)(tian)(tian)(tian)(tian)材料(liao)为粉细砂(sha)(sha)。填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)施(shi)工(gong)(gong)会(hui)受环境因素影(ying)响，需要(yao)(yao)在(zai)(zai)低(di)水(shui)位(wei)(wei)情况(kuang)下填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)，不(bu)同规格的(de)(de)(de)(de)膜(mo)(mo)(mo)(mo)袋(dai)灌(guan)(guan)砂(sha)(sha)口数(shu)量(liang)不(bu)同，最(zui)(zui)(zui)多可达到(dao)6个(ge)，最(zui)(zui)(zui)少2个(ge)，分别用(yong)(yong)于(yu)进(jin)砂(sha)(sha)和(he)排水(shui)。填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)灌(guan)(guan)入(ru)(ru)填(tian)(tian)(tian)(tian)(tian)(tian)(tian)料(liao)满后(hou)(hou)，使用(yong)(yong)泥(ni)浆泵(beng)冲砂(sha)(sha)处(chu)理(li)，将混合物抽到(dao)袖口内(nei)，随后(hou)(hou)封闭(bi)处(chu)理(li)。抽入(ru)(ru)的(de)(de)(de)(de)膜(mo)(mo)(mo)(mo)袋(dai)会(hui)固结(jie)，并形成(cheng)固化(hua)物。填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)灌(guan)(guan)入(ru)(ru)期(qi)间，对(dui)(dui)于(yu)袖口数(shu)量(liang)较多的(de)(de)(de)(de)膜(mo)(mo)(mo)(mo)袋(dai)，则(ze)采用(yong)(yong)对(dui)(dui)称冲砂(sha)(sha)的(de)(de)(de)(de)施(shi)工(gong)(gong)，存在(zai)(zai)凹部位(wei)(wei)时，则(ze)应(ying)进(jin)行二次(ci)充(chong)灌(guan)(guan)。对(dui)(dui)于(yu)围堰(yan)主体(ti)(ti)位(wei)(wei)置(zhi)(zhi)的(de)(de)(de)(de)膜(mo)(mo)(mo)(mo)袋(dai)充(chong)灌(guan)(guan)施(shi)工(gong)(gong)，则(ze)采用(yong)(yong)分层充(chong)灌(guan)(guan)的(de)(de)(de)(de)方法，严(yan)格控(kong)制(zhi)(zhi)流量(liang)、流速(su)等(deng)工(gong)(gong)艺参(can)数(shu)，并在(zai)(zai)填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)期(qi)间调整(zheng)泵(beng)管头(tou)位(wei)(wei)置(zhi)(zhi)，以(yi)保(bao)障膜(mo)(mo)(mo)(mo)袋(dai)的(de)(de)(de)(de)平(ping)整(zheng)性，高(gao)差(cha)应(ying)控(kong)制(zhi)(zhi)在(zai)(zai)0.1m以(yi)内(nei)。首次(ci)填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)完(wan)成(cheng)后(hou)(hou)，二次(ci)填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)需要(yao)(yao)在(zai)(zai)泌水(shui)后(hou)(hou)进(jin)行，泌水(shui)最(zui)(zui)(zui)短时间应(ying)控(kong)制(zhi)(zhi)在(zai)(zai)20min以(yi)上，且需要(yao)(yao)严(yan)格控(kong)制(zhi)(zhi)袖口、袋(dai)体(ti)(ti)位(wei)(wei)置(zhi)(zhi)的(de)(de)(de)(de)平(ping)整(zheng)度(du)(du)、饱(bao)和(he)度(du)(du)，减少局(ju)部误差(cha)的(de)(de)(de)(de)产(chan)(chan)生。填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)完(wan)成(cheng)后(hou)(hou)，袋(dai)体(ti)(ti)可能(neng)存在(zai)(zai)超高(gao)部位(wei)(wei)，该(gai)部位(wei)(wei)需要(yao)(yao)使用(yong)(yong)水(shui)枪(qiang)清扫。填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)后(hou)(hou)，检查袋(dai)体(ti)(ti)的(de)(de)(de)(de)厚度(du)(du)，厚度(du)(du)需要(yao)(yao)满足最(zui)(zui)(zui)高(gao)0.6m的(de)(de)(de)(de)基本要(yao)(yao)求，密实后(hou)(hou)应(ying)满足最(zui)(zui)(zui)高(gao)0.5m的(de)(de)(de)(de)基本要(yao)(yao)求。在(zai)(zai)底层填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)完(wan)成(cheng)后(hou)(hou)，检验填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)的(de)(de)(de)(de)质(zhi)量(liang)，随后(hou)(hou)进(jin)行上层位(wei)(wei)置(zhi)(zhi)的(de)(de)(de)(de)填(tian)(tian)(tian)(tian)(tian)(tian)(tian)充(chong)施(shi)工(gong)(gong)。

整(zheng)(zheng)个填(tian)(tian)充(chong)铺设过程(cheng)应(ying)严格按(an)照顺序作业，从(cong)低洼(wa)位(wei)置(zhi)开始到围堰(yan)主体(ti)中心(xin)，最(zui)后(hou)在上下游侧填(tian)(tian)充(chong)，整(zheng)(zheng)个填(tian)(tian)充(chong)结构(gou)立(li)体(ti)、交错(cuo)，不断上升(sheng)，以确保(bao)整(zheng)(zheng)体(ti)结构(gou)的(de)稳定性。同时，严格控(kong)(kong)制填(tian)(tian)筑的(de)速度(du)，每层(ceng)间隔时间应(ying)控(kong)(kong)制在1d以上，直至填(tian)(tian)充(chong)达到高程(cheng)后(hou)停止(zhi)。在围堰(yan)的(de)整(zheng)(zheng)体(ti)填(tian)(tian)充(chong)完成之后(hou)，处(chu)理(li)围堰(yan)主体(ti)迎(ying)水坡(po)位(wei)置(zhi)，保(bao)持其平整(zheng)(zheng)度(du)。铺设所使用(yong)的(de)材(cai)料为防渗土(tu)工(gong)膜(mo)，土(tu)工(gong)膜(mo)嵌(qian)入到底部为止(zhi)，距离控(kong)(kong)制在0.5m左右。防渗土(tu)工(gong)膜(mo)需要(yao)(yao)使用(yong)袋装(zhuang)砂(sha)压(ya)实，并在底部位(wei)置(zhi)安(an)装(zhuang)砂(sha)垫层(ceng)、压(ya)脚，确保(bao)围堰(yan)的(de)耐久(jiu)性能够满(man)足(zu)要(yao)(yao)求，可(ke)以抵抗(kang)水流(liu)、风浪等。