真空預壓沉降監測

真(zhen)(zhen)(zhen)空預壓(ya)(ya)法就是在需要加固(gu)(gu)的(de)(de)(de)軟基(ji)中(zhong)插入豎(shu)向(xiang)排水(shui)通(tong)道（如砂(sha)井、袋裝砂(sha)井或塑料排水(shui)板等(deng)(deng)），然(ran)后(hou)在地面鋪(pu)設(she)(she)一(yi)層(ceng)(ceng)砂(sha)墊層(ceng)(ceng)，再在其上(shang)(shang)覆蓋一(yi)層(ceng)(ceng)不透氣的(de)(de)(de)薄(bo)膜(mo)。在膜(mo)下抽真(zhen)(zhen)(zhen)空形成負壓(ya)(ya)（相對(dui)大氣壓(ya)(ya)而言)），負壓(ya)(ya)沿豎(shu)向(xiang)排水(shui)通(tong)道向(xiang)下傳(chuan)遞(di) 土(tu)(tu)體與(yu)豎(shu)向(xiang)排水(shui)通(tong)道的(de)(de)(de)不等(deng)(deng)壓(ya)(ya)狀態又使(shi)負壓(ya)(ya)向(xiang)土(tu)(tu)體中(zhong)傳(chuan)遞(di)，在負壓(ya)(ya)作(zuo)用(yong)(yong)(yong)下，孔隙水(shui)逐漸滲流(liu)到(dao)豎(shu)向(xiang)排水(shui)通(tong)道中(zhong)而達到(dao)土(tu)(tu)體排水(shui)固(gu)(gu)結、強度增長的(de)(de)(de)效果。真(zhen)(zhen)(zhen)空預壓(ya)(ya)法作(zuo)為新一(yi)代軟基(ji)加固(gu)(gu)方法，以其工(gong)期短、施工(gong)安全、無污染環境、費用(yong)(yong)(yong)低等(deng)(deng)優點而廣泛應用(yong)(yong)(yong)于港口(kou)、碼頭、機場(chang)、工(gong)業與(yu)民用(yong)(yong)(yong)建筑(zhu)等(deng)(deng)工(gong)程建設(she)(she)，但理論研(yan)究的(de)(de)(de)落后(hou)限制了其工(gong)程上(shang)(shang)的(de)(de)(de)進一(yi)步推廣應用(yong)(yong)(yong)。用(yong)(yong)(yong)真(zhen)(zhen)(zhen)空預壓(ya)(ya)加固(gu)(gu)軟土(tu)(tu)地基(ji)，在固(gu)(gu)結過程中(zhong)不僅土(tu)(tu)體產生垂直沉降，側向(xiang)也會產生向(xiang)著負壓(ya)(ya)源(yuan)的(de)(de)(de)水(shui)平(ping)位(wei)移。當在真(zhen)(zhen)(zhen)空預壓(ya)(ya)的(de)(de)(de)影響范(fan)圍內有其他建筑(zhu)設(she)(she)施時，使(shi)用(yong)(yong)(yong)該法可能(neng)會危(wei)及其上(shang)(shang)部結構物的(de)(de)(de)安全。真(zhen)(zhen)(zhen)空預壓(ya)(ya)法施工(gong)流(liu)程如下：測(ce)(ce)量放線→鋪(pu)設(she)(she)主支濾排水(shui)管→鋪(pu)設(she)(she)上(shang)(shang)層(ceng)(ceng)砂(sha)墊層(ceng)(ceng)→砂(sha)面整(zheng)平(ping)→鋪(pu)設(she)(she)聚(ju)氯乙烯(xi)薄(bo)膜(mo)→施工(gong)密(mi)封溝→設(she)(she)置測(ce)(ce)量標志→安裝真(zhen)(zhen)(zhen)空泵→抽真(zhen)(zhen)(zhen)空預壓(ya)(ya)固(gu)(gu)結土(tu)(tu)層(ceng)(ceng)。