岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2014年
5期
1295-1302
,共8页
FBG光纤传感技术%开口PHC管桩%贯入阻力分离%桩身应力%临界深度
FBG光纖傳感技術%開口PHC管樁%貫入阻力分離%樁身應力%臨界深度
FBG광섬전감기술%개구PHC관장%관입조력분리%장신응력%림계심도
FBG optical fiber sensing technology%opened PHC pipe piles%penetration resistance separation%pile stress%critical depth
压桩过程中PHC管桩侧摩阻力与端阻力的分离是制约其贯入机制及承载力研究的瓶颈。通过桩身预埋准分布式FBG光纤传感器，对贯入成层土地基中5根足尺开口PHC管桩侧摩阻力及端阻力发展变化情况进行了监测。试验表明，准分布式光纤传感测试技术现场可操作性强，粗放施工环境下贯入阻力分离效果较为理想。成层土地基中压桩力曲线基本反映地层土性变化，桩端土层性状对压桩力影响较大。硬质土层界面处试桩压桩力平均增幅约为64.06%，端阻力受地层变化影响更为显著，平均增长幅度约为97.41%，侧摩阻力平均增长幅度约为17.92%；桩端位于非硬质土层试桩压桩力变化不明显。贯入过程中现场足尺试验桩身应力变化不同于室内模型试验，桩身上、下部侧摩阻力发挥的力学机制不同。受现场粗放施工条件及深度方向土层变化影响，贯入成层土地基中桩侧摩阻力临界深度现象不明显。
壓樁過程中PHC管樁側摩阻力與耑阻力的分離是製約其貫入機製及承載力研究的瓶頸。通過樁身預埋準分佈式FBG光纖傳感器，對貫入成層土地基中5根足呎開口PHC管樁側摩阻力及耑阻力髮展變化情況進行瞭鑑測。試驗錶明，準分佈式光纖傳感測試技術現場可操作性彊，粗放施工環境下貫入阻力分離效果較為理想。成層土地基中壓樁力麯線基本反映地層土性變化，樁耑土層性狀對壓樁力影響較大。硬質土層界麵處試樁壓樁力平均增幅約為64.06%，耑阻力受地層變化影響更為顯著，平均增長幅度約為97.41%，側摩阻力平均增長幅度約為17.92%；樁耑位于非硬質土層試樁壓樁力變化不明顯。貫入過程中現場足呎試驗樁身應力變化不同于室內模型試驗，樁身上、下部側摩阻力髮揮的力學機製不同。受現場粗放施工條件及深度方嚮土層變化影響，貫入成層土地基中樁側摩阻力臨界深度現象不明顯。
압장과정중PHC관장측마조력여단조력적분리시제약기관입궤제급승재력연구적병경。통과장신예매준분포식FBG광섬전감기，대관입성층토지기중5근족척개구PHC관장측마조력급단조력발전변화정황진행료감측。시험표명，준분포식광섬전감측시기술현장가조작성강，조방시공배경하관입조력분리효과교위이상。성층토지기중압장력곡선기본반영지층토성변화，장단토층성상대압장력영향교대。경질토층계면처시장압장력평균증폭약위64.06%，단조력수지층변화영향경위현저，평균증장폭도약위97.41%，측마조력평균증장폭도약위17.92%；장단위우비경질토층시장압장력변화불명현。관입과정중현장족척시험장신응력변화불동우실내모형시험，장신상、하부측마조력발휘적역학궤제불동。수현장조방시공조건급심도방향토층변화영향，관입성층토지기중장측마조력림계심도현상불명현。
The separation of side resistance and toe resistance of PHC pipe piles during installation restricts the study of its penetration mechanism and bearing capacity. Full-scale tests are conducted on 5 opened PHC pipe piles jacked into stratified soils to monitor the variation of side resistance and toe resistance during installation base on quasi-distributed Fiber Bragg grating sensors. The results indicate that quasi-distributed optical fiber technology has strong operability and installation resistance separation is obtained well under bad construction condition. The variation of pile jacking force in stratified soils basically reflects the soil parameters difference, and the soil under pile toe has more influence on jacking force. The test piles jacking force, which pile toe locates on bearing layer, increases about 64.06% when jacks into the bearing layer, while the increment of toe resistance and side resistance are 97.41%and 17.92%, respectively;The pile jacking force variation is not significant which toe doesn’t locate on bearing layer. The variation of pile stress in field test is different from indoor experiments during installation, in which the mechanism of side resistance in upper is different with bottom; and the critical depth phenomenon of side resistance is not obvious because of bad construction condition and soil variation in depth.
