舊城改造施工引發的房屋裂縫分析及處理
發布時間:2014-08-05
簡介:chenggaizaoshigongyinfadezhoubianfangwuliefengwentishiwoshijianzhuxingyepubiancunzaidewenti,benwenduicileiliefengdechanshenghefazhanjinxingfenxi,bingtichuchuliyijian,gongqitajiuchenggaizaojianshezhehexiangguanzhuhucankao
關鍵字:舊城改造,變形裂縫,地下降水,觀測,安全鑒定,裂縫修複
隨著我國經濟的迅猛發展,可開發的建築用地日益減少,而城中村由於使用年限長、waiguanpojiu,yanzhongyingxiangchengshimianmao。yinci,jiuchenggaizaochengweimuqianfangdichankaifadedashisuoqu。zaijiuchenggaizaozhong,youyugeshigongduanshigongdeshijianbuyi,zhoubianjianzhushoushigongdeyingxiangpubianchuxianfangwuliefengdengwenti,benwenzhenduiciwentijinxingfenxi。
工程案例:位wei於yu深shen圳zhen市shi南nan山shan區qu一yi甲jia村cun的de某mou商shang住zhu樓lou工gong程cheng,地di下xia室shi兩liang層ceng,地di上shang二er十shi五wu層ceng,周zhou邊bian均jun為wei七qi八ba十shi年nian代dai建jian設she的de民min房fang,天tian然ran基ji礎chu,層ceng高gao為wei一yi至zhi四si層ceng不bu等deng。由you於yu基ji礎chu施shi工gong造zao成cheng南nan麵mian部bu分fen房fang屋wu牆qiang麵mian、地麵裂縫,裂縫最寬處達1.5厘米寬。開發商和施工單位對此非常重視,在基礎施工期間,對基坑的沉降、位wei移yi和he裂lie縫feng進jin行xing連lian續xu的de觀guan測ce。同tong時shi,建jian設she局ju和he質zhi監jian站zhan等deng有you關guan領ling導dao也ye非fei常chang關guan注zhu此ci事shi,多duo次ci到dao工gong地di現xian場chang指zhi導dao工gong作zuo。為wei了le安an全quan起qi見jian,開kai發fa商shang委wei托tuo中zhong國guo建jian築zhu科ke學xue研yan究jiu院yuan深shen圳zhen分fen院yuan對dui裂lie縫feng最zui寬kuan的de房fang屋wu進jin行xing結jie構gou安an全quan鑒jian定ding,檢jian測ce結jie果guo該gai房fang屋wu滿man足zu安an全quan及ji使shi用yong要yao求qiu。在zai該gai工gong程cheng基ji礎chu完wan工gong後hou,裂lie縫feng的de發fa展zhan已yi經jing穩wen定ding,施shi工gong單dan位wei組zu織zhi對dui裂lie縫feng進jin行xing修xiu複fu,從cong而er圓yuan滿man解jie決jue了le此ci事shi。
在舊城改造中,由於新建建築物多為高層建築,地下室有一至三層不等。在基坑開挖施工過程中,周邊建築物經常受此影響產生牆麵、地麵裂縫。就此裂縫的產生而言,主要有以下幾方麵的原因:
1. 基(ji)坑(keng)邊(bian)距(ju)離(li)建(jian)築(zhu)物(wu)太(tai)近(jin)。由(you)於(yu)城(cheng)中(zhong)村(cun)建(jian)築(zhu)物(wu)密(mi)集(ji),開(kai)發(fa)時(shi)按(an)紅(hong)線(xian)劃(hua)分(fen)後(hou),相(xiang)鄰(lin)地(di)塊(kuai)開(kai)發(fa)時(shi)間(jian)不(bu)同(tong),造(zao)成(cheng)部(bu)分(fen)建(jian)築(zhu)物(wu)離(li)基(ji)坑(keng)的(de)距(ju)離(li)太(tai)近(jin),有(you)些(xie)房(fang)屋(wu)離(li)基(ji)坑(keng)的(de)距(ju)離(li)甚(shen)至(zhi)在(zai)五(wu)米(mi)以(yi)內(nei)。而(er)舊(jiu)城(cheng)改(gai)造(zao)項(xiang)目(mu)很(hen)多(duo)受(shou)到(dao)施(shi)工(gong)場(chang)地(di)限(xian)製(zhi),隻(zhi)能(neng)垂(chui)直(zhi)開(kai)挖(wa),在(zai)開(kai)挖(wa)過(guo)程(cheng)中(zhong)勢(shi)必(bi)影(ying)響(xiang)附(fu)近(jin)的(de)建(jian)築(zhu)物(wu)。
2. 基ji坑keng支zhi護hu進jin度du與yu錨mao固gu措cuo施shi的de影ying響xiang。在zai基ji坑keng支zhi護hu過guo程cheng中zhong,必bi須xu采cai取qu分fen層ceng開kai挖wa,及ji時shi支zhi護hu的de措cuo施shi,才cai能neng確que保bao基ji坑keng的de安an全quan。如ru果guo土tu方fang開kai挖wa後hou不bu及ji時shi支zhi護hu,容rong易yi造zao成cheng土tu方fang塌ta落luo,產chan生sheng周zhou邊bian建jian築zhu基ji礎chu下xia沉chen、牆地麵開裂等嚴重後果。而且基坑支護應並且盡量避免雨季施工。另外,錨固的深度對基坑的安全也是至關重要的。
3. 地(di)下(xia)降(jiang)水(shui)的(de)影(ying)響(xiang)。由(you)於(yu)基(ji)礎(chu)施(shi)工(gong)過(guo)程(cheng)中(zhong)必(bi)須(xu)保(bao)證(zheng)基(ji)坑(keng)內(nei)無(wu)水(shui)作(zuo)業(ye),因(yin)此(ci)施(shi)工(gong)中(zhong)要(yao)采(cai)取(qu)連(lian)續(xu)降(jiang)水(shui)措(cuo)施(shi),這(zhe)勢(shi)必(bi)造(zao)成(cheng)大(da)麵(mian)積(ji)地(di)下(xia)水(shui)位(wei)下(xia)降(jiang),從(cong)而(er)大(da)大(da)減(jian)少(shao)了(le)周(zhou)邊(bian)建(jian)築(zhu)物(wu)的(de)基(ji)礎(chu)土(tu)層(ceng)含(han)水(shui)量(liang)。而(er)舊(jiu)城(cheng)中(zhong)多(duo)數(shu)建(jian)築(zhu)均(jun)為(wei)天(tian)然(ran)基(ji)礎(chu),承(cheng)載(zai)能(neng)力(li)差(cha),容(rong)易(yi)引(yin)起(qi)不(bu)均(jun)勻(yun)沉(chen)降(jiang),從(cong)而(er)產(chan)生(sheng)裂(lie)縫(feng)。這(zhe)是(shi)導(dao)致(zhi)舊(jiu)城(cheng)改(gai)造(zao)周(zhou)邊(bian)建(jian)築(zhu)裂(lie)縫(feng)的(de)最(zui)主(zhu)要(yao)的(de)原(yuan)因(yin)。
據(ju)此(ci)分(fen)析(xi),舊(jiu)城(cheng)改(gai)造(zao)中(zhong)施(shi)工(gong)引(yin)發(fa)的(de)裂(lie)縫(feng)屬(shu)於(yu)變(bian)形(xing)裂(lie)縫(feng)。變(bian)形(xing)裂(lie)縫(feng)一(yi)般(ban)有(you)三(san)個(ge)階(jie)段(duan),一(yi)是(shi)潛(qian)伏(fu)期(qi),二(er)是(shi)發(fa)展(zhan)期(qi),三(san)是(shi)穩(wen)定(ding)期(qi)。此(ci)種(zhong)裂(lie)縫(feng)的(de)修(xiu)複(fu)一(yi)定(ding)要(yao)掌(zhang)握(wo)時(shi)機(ji),當(dang)裂(lie)縫(feng)進(jin)入(ru)穩(wen)定(ding)期(qi)不(bu)再(zai)發(fa)展(zhan)時(shi),一(yi)次(ci)性(xing)修(xiu)複(fu),不(bu)會(hui)再(zai)裂(lie)。
如何處理基礎沉降造成的裂縫?解決的方法應從沉降問題著手。好比一個人內髒有了毛病,總要有些咳嗽、發燒的外部現象,但隻治咳嗽、發fa燒shao的de外wai部bu現xian象xiang是shi去qu不bu了le病bing的de,因yin為wei沒mei治zhi本ben。沉chen降jiang引yin起qi的de裂lie縫feng,不bu管guan沉chen降jiang,隻zhi修xiu裂lie縫feng,再zai好hao的de修xiu複fu方fang法fa,也ye抵di抗kang不bu了le沉chen降jiang的de變bian形xing力li,修xiu完wan肯ken定ding還hai要yao裂lie。因yin此ci,發fa現xian裂lie縫feng時shi,我wo們men不bu應ying急ji於yu維wei修xiu,而er是shi要yao做zuo好hao各ge項xiang觀guan測ce工gong作zuo,包bao括kuo觀guan測ce裂lie縫feng的de發fa展zhan、基坑的沉降、位移等,待沉降及位移趨於穩定後,進行一次性修複。具體的來說,應該從以下幾方麵著手:
1. 在施工過程中加強觀測。在基坑開挖、樁基施工、dixiashijiegoushigongqijian,guancejikengdechenjiangjiweiyishishouyaogongzuo。tebieshizaijikengkaiwaguochengzhong,meikaiwayicengbixuguanceyici,erqiemeicengkaiwadeshenduyingkongzhizai1.5米以內,根據不同的土質情況可適當調整。當沉降或位移值超過規範允許範圍時,應立即采取相應措施處理。
2. 采cai取qu隨sui挖wa隨sui支zhi護hu的de分fen層ceng開kai挖wa支zhi護hu措cuo施shi。特te別bie是shi靠kao近jin建jian築zhu物wu的de部bu位wei,施shi工gong單dan位wei應ying該gai重zhong點dian突tu擊ji,隨sui挖wa隨sui支zhi護hu,不bu宜yi讓rang開kai挖wa層ceng暴bao露lu時shi間jian太tai長chang。同tong時shi,應ying加jia強qiang薄bo弱ruo部bu位wei的de錨mao索suo或huo土tu釘ding密mi度du及ji深shen度du,確que保bao基ji坑keng的de穩wen定ding。
3. helixuanyongzhuangxing,jianshaozhuangjishigongshizhendongdeyingxiang。duiyujiuchenggaizaoxiangmujichuzhuangxing,yingjinshenkaolv,bingduigezhongzhuangxingzuojishujingjibijiao。weijianshaoduizhoubianjianzhudeyingxiang,jianyicaiyongjingyazhuang。rucaiquchuijizhuang,yingcaiqucuoshigelizhoubianjianzhu,ruwafangzhengoudeng。
4. 加快基礎工程施工。由於降水是造成周邊建築裂縫的主要原因,所以,盡早停止降水是阻止裂縫發展的有效措施。隻有基礎工程(即地下室)完工後,降水作業停止,基坑得以回填,沉降及位移將趨於穩定,裂縫也不再發展。
5. 采cai取qu必bi要yao的de結jie構gou安an全quan鑒jian定ding。房fang屋wu出chu現xian裂lie縫feng後hou,住zhu戶hu和he發fa展zhan商shang都dou應ying對dui此ci類lei問wen題ti持chi積ji極ji處chu理li的de態tai度du,若ruo對dui裂lie縫feng的de發fa展zhan表biao示shi懷huai疑yi或huo認ren為wei有you危wei險xian時shi,可ke委wei托tuo具ju有you相xiang關guan資zi質zhi的de安an全quan鑒jian定ding機ji構gou進jin行xing結jie構gou安an全quan鑒jian定ding,從cong而er判pan定ding房fang屋wu的de結jie構gou安an全quan性xing能neng及ji使shi用yong性xing能neng,並bing對dui裂lie縫feng的de維wei修xiu提ti出chu建jian議yi。
舊(jiu)城(cheng)改(gai)造(zao)有(you)利(li)於(yu)我(wo)市(shi)國(guo)建(jian)設(she)和(he)發(fa)展(zhan),是(shi)利(li)國(guo)利(li)民(min)的(de)大(da)事(shi),我(wo)們(men)應(ying)該(gai)積(ji)極(ji)地(di)支(zhi)持(chi)和(he)配(pei)合(he)此(ci)項(xiang)工(gong)作(zuo)。如(ru)果(guo)在(zai)舊(jiu)城(cheng)改(gai)造(zao)中(zhong)遇(yu)到(dao)上(shang)述(shu)問(wen)題(ti),作(zuo)為(wei)住(zhu)戶(hu),應(ying)該(gai)積(ji)極(ji)配(pei)合(he)施(shi)工(gong)單(dan)位(wei)做(zuo)好(hao)觀(guan)測(ce)工(gong)作(zuo),配(pei)合(he)有(you)關(guan)單(dan)位(wei)分(fen)析(xi)和(he)處(chu)理(li)裂(lie)縫(feng),不(bu)必(bi)產(chan)生(sheng)裂(lie)縫(feng)恐(kong)懼(ju)感(gan)或(huo)將(jiang)問(wen)題(ti)誇(kua)大(da);作為發展商和施工單位,應參考以上意見對裂縫進行觀測和處理,對住戶的疑問進行耐心的解釋,共同分析和解決問題。