岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2014年
z1期
221-226
,共6页
加筋与遮帘效应%相互作用系数%群桩沉降%剪切变形法%成层地基
加觔與遮簾效應%相互作用繫數%群樁沉降%剪切變形法%成層地基
가근여차렴효응%상호작용계수%군장침강%전절변형법%성층지기
reinforcing and restraining effect%interaction coefficient%pile group settlement%shear displacement method%multi-layered soils
群桩中各基桩在地基土中的加筋与遮帘效应是客观存在的,然而,在目前的桩基沉降理论与实践中,相关的研究仍显不足。基于剪切变形法理论,考虑桩的加筋与遮帘效应,求得各基桩在自身桩顶荷载作用下产生的沉降以及其引起相邻桩的附加沉降量,由此提出群桩中任两桩的相互作用系数简化公式,同时,也得到各基桩桩侧及桩端桩-土接触等效弹簧刚度,并基于荷载传递法原理,建立了成层地基条件下各基桩在自身桩顶荷载作用下的桩身位移平衡方程,推导出各土层层顶处桩身沉降、轴力与层底处桩身沉降、轴力之间的递推关系,进而将公式推广到高、低承台群桩基础计算中。工程算例分析表明,用该方法计算有较高的精度,求得的荷载-沉降曲线及两桩相互作用系数与实测值吻合较好;相互作用系数要明显小于弹性理论计算结果。
群樁中各基樁在地基土中的加觔與遮簾效應是客觀存在的,然而,在目前的樁基沉降理論與實踐中,相關的研究仍顯不足。基于剪切變形法理論,攷慮樁的加觔與遮簾效應,求得各基樁在自身樁頂荷載作用下產生的沉降以及其引起相鄰樁的附加沉降量,由此提齣群樁中任兩樁的相互作用繫數簡化公式,同時,也得到各基樁樁側及樁耑樁-土接觸等效彈簧剛度,併基于荷載傳遞法原理,建立瞭成層地基條件下各基樁在自身樁頂荷載作用下的樁身位移平衡方程,推導齣各土層層頂處樁身沉降、軸力與層底處樁身沉降、軸力之間的遞推關繫,進而將公式推廣到高、低承檯群樁基礎計算中。工程算例分析錶明,用該方法計算有較高的精度,求得的荷載-沉降麯線及兩樁相互作用繫數與實測值吻閤較好;相互作用繫數要明顯小于彈性理論計算結果。
군장중각기장재지기토중적가근여차렴효응시객관존재적,연이,재목전적장기침강이론여실천중,상관적연구잉현불족。기우전절변형법이론,고필장적가근여차렴효응,구득각기장재자신장정하재작용하산생적침강이급기인기상린장적부가침강량,유차제출군장중임량장적상호작용계수간화공식,동시,야득도각기장장측급장단장-토접촉등효탄황강도,병기우하재전체법원리,건립료성층지기조건하각기장재자신장정하재작용하적장신위이평형방정,추도출각토층층정처장신침강、축력여층저처장신침강、축력지간적체추관계,진이장공식추엄도고、저승태군장기출계산중。공정산례분석표명,용해방법계산유교고적정도,구득적하재-침강곡선급량장상호작용계수여실측치문합교호;상호작용계수요명현소우탄성이론계산결과。
The reinforcing and restraining effect of piles embedded in soils is objective existence. However, the correlative research work on pile groups settlement methods is not deep enough and needs to be continued. Based on the shear displacement method, considering the reinforcing and restraining effect, the settlements of the analyzing pile caused by loads on the pile top were calculated, including the reduction effect caused by the existence of the other adjacent piles. And the additional settlements of the adjacent piles arising from the settlement of the loaded pile were obtained as well. Thus a simplified formula of interaction coefficients between any two piles was presented. Meanwhile, the equivalent shear stiffness coefficients of soil around each pile were developed; and an equation of displacements caused by load on top of the analyzing pile imbedded in multi-layered soils was built; so recurrence relations of settlement and axial force of pile shaft between upper and lower of each pile sections were respectively deduced; in the process of deduction, Boussinesq solution was modified to include the effect of different embedded depths, and then used to derive the equivalent stiffness coefficients of the soil under the pile tips. Lastly, the formula was extended to the settlements calculation of high and low cap pile groups. Different methods were compared with two engineering cases. The results show that the load-settlement curve computed by present method agreed well with those measured from real engineering cases; and the calculating interaction coefficients are much less than ones calculated by the elastic theory method.