隧道建设
隧道建設
수도건설
TUNNEL CONSTRUCTION
2015年
6期
527-533
,共7页
软土地层%钢板桩拔除%既有隧道%数值模拟
軟土地層%鋼闆樁拔除%既有隧道%數值模擬
연토지층%강판장발제%기유수도%수치모의
soft soil%steel sheet pile%removing%existing tunnel%numerical simulation
钢板桩以其整体刚度大、打拔桩容易和施工速度快等优点被广泛应用于基坑工程中，但钢板桩在拔除后，土体极易留下孔隙，从而造成地面以及邻近建构筑物开裂。从钢板桩施工特点入手，采用数值模拟方法，对软土地层条件下钢板桩拔除后产生40，100，150，200 mm 4组孔隙宽度时对既有隧道位移和受力影响，以及地表变形等问题进行了分析。结果表明：孔隙宽度越大，既有隧道位移和受力也越大，在孔隙宽度为150 mm 时，拉应力增量为4．65 MPa，大于拉应力增量容许值的4．5倍；既有隧道邻近钢板桩侧的位移和受力较远离钢板桩侧要大得多；钢板桩拔除后产生的孔隙对其周边10 m 范围内的土体影响显著。由此提出优化拔桩顺序、减小拔桩带泥量、周边土体加固以及加密监测等工程措施，对类似地质条件下钢板桩拔除时邻近建构筑物的保护具有一定的借鉴意义。
鋼闆樁以其整體剛度大、打拔樁容易和施工速度快等優點被廣汎應用于基坑工程中，但鋼闆樁在拔除後，土體極易留下孔隙，從而造成地麵以及鄰近建構築物開裂。從鋼闆樁施工特點入手，採用數值模擬方法，對軟土地層條件下鋼闆樁拔除後產生40，100，150，200 mm 4組孔隙寬度時對既有隧道位移和受力影響，以及地錶變形等問題進行瞭分析。結果錶明：孔隙寬度越大，既有隧道位移和受力也越大，在孔隙寬度為150 mm 時，拉應力增量為4．65 MPa，大于拉應力增量容許值的4．5倍；既有隧道鄰近鋼闆樁側的位移和受力較遠離鋼闆樁側要大得多；鋼闆樁拔除後產生的孔隙對其週邊10 m 範圍內的土體影響顯著。由此提齣優化拔樁順序、減小拔樁帶泥量、週邊土體加固以及加密鑑測等工程措施，對類似地質條件下鋼闆樁拔除時鄰近建構築物的保護具有一定的藉鑒意義。
강판장이기정체강도대、타발장용역화시공속도쾌등우점피엄범응용우기갱공정중，단강판장재발제후，토체겁역류하공극，종이조성지면이급린근건구축물개렬。종강판장시공특점입수，채용수치모의방법，대연토지층조건하강판장발제후산생40，100，150，200 mm 4조공극관도시대기유수도위이화수력영향，이급지표변형등문제진행료분석。결과표명：공극관도월대，기유수도위이화수력야월대，재공극관도위150 mm 시，랍응력증량위4．65 MPa，대우랍응력증량용허치적4．5배；기유수도린근강판장측적위이화수력교원리강판장측요대득다；강판장발제후산생적공극대기주변10 m 범위내적토체영향현저。유차제출우화발장순서、감소발장대니량、주변토체가고이급가밀감측등공정조시，대유사지질조건하강판장발제시린근건구축물적보호구유일정적차감의의。
Due to the advantages of large integral stiffness,easy installing and removing and high construction speed,steel sheet piles are widely used in the excavation of foundation pits.When the steel sheet piles are removed,however,voids may be created in the soil strata,which may cause cracks of the ground surface and the neighboring buildings.In this paper,the influence of 4 void widths,i.e.,40 mm,100 mm,150 mm and 200 mm,produced by steel sheet pile removing on the displacement and stressing of the existing tunnel and the ground surface settlement are analyzed by means of numerical simulation and on basis of study on the construction characteristics of the steel sheet piles.The results show that:1)The displacement and stress of the existing tunnel increase as the void width increases.When the void width is 150 mm,the tensile stress increment is 4.65 MPa,which has exceeded the allowable tensile stress increment by 4.5 times;2)The displacement and stress of the existing tunnel close to the steel sheet piles are much larger than those of the existing tunnel far away from the steel sheet piles;3)The void produced by steel sheet pile removing has significant influence on the soil mass within the scope of 10 m around the void.In the end,countermeasures,including optimization of the steel sheet pile removing sequence,reducing the mud produced when steel sheet piles are removed,consolidation of surrounding soil mass and strengthening the monitoring,are proposed.The paper can provide reference for the protection of neighboring buildings when steel sheet piles are removed in similar soil conditions.
