岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2014年
7期
1899-1906
,共8页
黄土斜坡桩基%竖向承载特性%现场试验%区域性%承载力的折减
黃土斜坡樁基%豎嚮承載特性%現場試驗%區域性%承載力的摺減
황토사파장기%수향승재특성%현장시험%구역성%승재력적절감
pile foundation in loess slope%vertical bearing capacity%field test%regionalism%reduction of bearing capacity
结合某黄土斜坡桥梁桩基工程，对同一坡度相近位置的两根桩基开展现场试验，研究其在不同竖向荷载工况下的桩身上、下坡面两侧的轴力、桩侧摩阻力及桩侧土压力的传递规律与分布特征。试验表明：桩基荷载传递具有明显的区域性，第1区域是从桩顶至约3倍桩径深度处，此区域上坡面桩侧轴力较下坡面相应位置小，且其轴力随深度递减幅度及侧摩阻力发挥程度均较下坡面桩侧大；第2区域是从约3倍桩径至10倍桩径深度处，桩身上坡面一侧竖向受力减小幅度小于桩基下坡面一侧，但此时下坡面桩侧摩阻力发挥幅度大于桩基上坡面一侧；第3区域是从约10倍桩径直至桩端，该区桩身两侧轴力差异不大，摩阻力发挥幅度相近，荷载平衡协调且向下传递稳定。针对斜坡桥梁桩基上、下坡面两侧所受土压力的不均匀性，对设计桩基竖向承载力进行了一定程度地折减，并对计算公式作了相应修正，研究结论可供类似工程参考、借鉴。
結閤某黃土斜坡橋樑樁基工程，對同一坡度相近位置的兩根樁基開展現場試驗，研究其在不同豎嚮荷載工況下的樁身上、下坡麵兩側的軸力、樁側摩阻力及樁側土壓力的傳遞規律與分佈特徵。試驗錶明：樁基荷載傳遞具有明顯的區域性，第1區域是從樁頂至約3倍樁徑深度處，此區域上坡麵樁側軸力較下坡麵相應位置小，且其軸力隨深度遞減幅度及側摩阻力髮揮程度均較下坡麵樁側大；第2區域是從約3倍樁徑至10倍樁徑深度處，樁身上坡麵一側豎嚮受力減小幅度小于樁基下坡麵一側，但此時下坡麵樁側摩阻力髮揮幅度大于樁基上坡麵一側；第3區域是從約10倍樁徑直至樁耑，該區樁身兩側軸力差異不大，摩阻力髮揮幅度相近，荷載平衡協調且嚮下傳遞穩定。針對斜坡橋樑樁基上、下坡麵兩側所受土壓力的不均勻性，對設計樁基豎嚮承載力進行瞭一定程度地摺減，併對計算公式作瞭相應脩正，研究結論可供類似工程參攷、藉鑒。
결합모황토사파교량장기공정，대동일파도상근위치적량근장기개전현장시험，연구기재불동수향하재공황하적장신상、하파면량측적축력、장측마조력급장측토압력적전체규률여분포특정。시험표명：장기하재전체구유명현적구역성，제1구역시종장정지약3배장경심도처，차구역상파면장측축력교하파면상응위치소，차기축력수심도체감폭도급측마조력발휘정도균교하파면장측대；제2구역시종약3배장경지10배장경심도처，장신상파면일측수향수력감소폭도소우장기하파면일측，단차시하파면장측마조력발휘폭도대우장기상파면일측；제3구역시종약10배장경직지장단，해구장신량측축력차이불대，마조력발휘폭도상근，하재평형협조차향하전체은정。침대사파교량장기상、하파면량측소수토압력적불균균성，대설계장기수향승재력진행료일정정도지절감，병대계산공식작료상응수정，연구결론가공유사공정삼고、차감。
Combined with the pile foundation engineering constructed in loess slope for supporting super bridge, field experiments on two neighboring piles at the same slope region are conducted to investigate transmitted characteristics as well as distribution feature of axial force, skin friction and lateral earth pressure of both upslope side and downslope side under different vertical load cases. The test results show that load transmitting of pile foundation can be obviously classified into 3 regions. The first region covers from pile head to about the depth of three times pile diameter; within this region, the axial force developed in pile upslope side is less than corresponding position at downslope side; moreover, its decrease extent with pile depth and work efficiency of skin friction are greater than pile downslope side. The second region is within about pile depth of three times to ten times pile diameter, which shows a less axial force decrease extent with pile depth in upslope side and higher work efficiency of skin friction along downslope side at the same elevation. The third region starts from the pile depth of about ten times pile diameter and ends with pile tip. For pile body in this region, the difference of axial force and skin friction for two sides at the same elevation are insignificant;and the load from super region could be even and well-distributed transmitted downwards. For the special issue of uneven earth pressure of pile foundation installed in loess slope, certain reduction in some degree for vertical bearing capacity of pile design is conducted;and some necessary revision of the calculation formula is made. The acquired study results can provide a reference for other similar pile foundation.
