中山大学学报（自然科学版）
中山大學學報（自然科學版）
중산대학학보（자연과학판）
ACTA SCIENTIARUM NATURALIUM UNIVERSITATIS SUNYATSENI
2015年
1期
130-135
,共6页
端承型静压桩%桩侧阻力%承载力时效性%干摩擦%湿摩擦
耑承型靜壓樁%樁側阻力%承載力時效性%榦摩抆%濕摩抆
단승형정압장%장측조력%승재력시효성%간마찰%습마찰
end bearing jacked pile%shaft resistance of pile%timeliness of bearing capacity%unlubrica-tion friction%lubrication friction
静压桩承载力的时效性主要由桩侧摩阻力的时效性引起，沉桩结束时桩侧摩擦的性状及其发挥程度将直接影响承载力的时效性。但是，目前承载力时效性的研究直接用终压力和承载力进行相关性研究而未考虑这一影响。因此本文将选择珠三角典型地层，进行模型桩的静力压入试验及其后的载荷试验，从摩擦学的角度研究桩端阻力变化对桩侧摩阻力发挥的影响机理，并进一步研究其对承载力时效性的影响。研究表明，沉桩过程中沉桩速度因桩压入不同性质土层、局部硬层及较硬的桩端持力层而发生变化，桩土之间的摩擦状态不断在干、湿摩擦之间转变，桩侧摩阻力的发挥随之变化。终压时桩侧若为干摩擦，则承载力时效性不明显，若为湿摩擦则时效性显著，即可利用终压时桩侧摩擦的性质和发挥程度来判断单桩承载力的时效性。
靜壓樁承載力的時效性主要由樁側摩阻力的時效性引起，沉樁結束時樁側摩抆的性狀及其髮揮程度將直接影響承載力的時效性。但是，目前承載力時效性的研究直接用終壓力和承載力進行相關性研究而未攷慮這一影響。因此本文將選擇珠三角典型地層，進行模型樁的靜力壓入試驗及其後的載荷試驗，從摩抆學的角度研究樁耑阻力變化對樁側摩阻力髮揮的影響機理，併進一步研究其對承載力時效性的影響。研究錶明，沉樁過程中沉樁速度因樁壓入不同性質土層、跼部硬層及較硬的樁耑持力層而髮生變化，樁土之間的摩抆狀態不斷在榦、濕摩抆之間轉變，樁側摩阻力的髮揮隨之變化。終壓時樁側若為榦摩抆，則承載力時效性不明顯，若為濕摩抆則時效性顯著，即可利用終壓時樁側摩抆的性質和髮揮程度來判斷單樁承載力的時效性。
정압장승재력적시효성주요유장측마조력적시효성인기，침장결속시장측마찰적성상급기발휘정도장직접영향승재력적시효성。단시，목전승재력시효성적연구직접용종압력화승재력진행상관성연구이미고필저일영향。인차본문장선택주삼각전형지층，진행모형장적정력압입시험급기후적재하시험，종마찰학적각도연구장단조력변화대장측마조력발휘적영향궤리，병진일보연구기대승재력시효성적영향。연구표명，침장과정중침장속도인장압입불동성질토층、국부경층급교경적장단지력층이발생변화，장토지간적마찰상태불단재간、습마찰지간전변，장측마조력적발휘수지변화。종압시장측약위간마찰，칙승재력시효성불명현，약위습마찰칙시효성현저，즉가이용종압시장측마찰적성질화발휘정도래판단단장승재력적시효성。
Time-dependent capacity increase of jacked piles is caused by the timeliness of shaft resist-ance and is affected directly by the character and mobilization of shaft resistance at the end of pile instal-lation.However,the previous researches on the time-dependent capacity always relies on the correlation study between the pile installation resistance and its bearing capacity tested by load test,while the influ-ence of the total shaft resistance at the end of pile installation on timeliness has been seldom considered . In this paper,jacking installation tests of model piles and load tests after installation are conducted to study the influence of base resistance on shaft resistance and further influence on the timeliness of bearing capacity of jacked pile with the theory of tribology in the Pearl River Delta.The study reveals that the friction at the pile-soil interface changes between lubricated friction and unlubricated friction during the whole pile installation.This phenomenon is caused by the change of installation velocity of the jacked pile when inserting different soil layers.If the pile shaft friction is unlubricated friction,then there is almost no time-dependent capacity increase,if the pile shaft friction is lubricated friction,then the timeliness of bearing capacity is very significant.That means the shaft friction condition of pile can be used to predic-tion the timeliness of bearing capacity.
