工程地质学报
工程地質學報
공정지질학보
2015年
1期
178-185
,共8页
加筋与遮帘效应%群桩沉降%层状地基%等效刚度%柔度系数矩阵
加觔與遮簾效應%群樁沉降%層狀地基%等效剛度%柔度繫數矩陣
가근여차렴효응%군장침강%층상지기%등효강도%유도계수구진
Reinforcing and restraining effect%Piles group settlement%Layered soil%Equivalent stiffness%Flexibility coefficient matrix
桩群在土中的加筋与遮帘效应是客观存在的，但目前的理论与实践均未能或有效地考虑该效应。基于剪切变形法原理，在计算某一根桩沉降时，考虑了其他各相邻基桩的存在对该桩沉降的折减，即加筋与遮帘效应，得到了桩侧桩－土接触等效剪切弹簧刚度，建立了桩身位移微分方程，分别求得桩顶沉降－桩端沉降、桩顶荷载－桩端压力的递推关系，从而得到了各桩在自身荷载作用下引起自身沉降的柔度系数；同理，也求得了各邻桩在其桩顶荷载下引起它桩沉降的柔度系数，最终建立了群桩沉降计算的柔度矩阵方程。推导过程中，考虑了地基土的成层性及桩端沉降的相互影响，并提出了基于一定深度内的Mindlin 位移解且考虑桩径影响的桩端压力－桩端位移关系新模式。算例结果表明，本文方法与实测值较为接近，且按本文方法求得的群桩中基桩相互作用系数明显小于弹性理论计算结果，且与实测值吻合较好。
樁群在土中的加觔與遮簾效應是客觀存在的，但目前的理論與實踐均未能或有效地攷慮該效應。基于剪切變形法原理，在計算某一根樁沉降時，攷慮瞭其他各相鄰基樁的存在對該樁沉降的摺減，即加觔與遮簾效應，得到瞭樁側樁－土接觸等效剪切彈簧剛度，建立瞭樁身位移微分方程，分彆求得樁頂沉降－樁耑沉降、樁頂荷載－樁耑壓力的遞推關繫，從而得到瞭各樁在自身荷載作用下引起自身沉降的柔度繫數；同理，也求得瞭各鄰樁在其樁頂荷載下引起它樁沉降的柔度繫數，最終建立瞭群樁沉降計算的柔度矩陣方程。推導過程中，攷慮瞭地基土的成層性及樁耑沉降的相互影響，併提齣瞭基于一定深度內的Mindlin 位移解且攷慮樁徑影響的樁耑壓力－樁耑位移關繫新模式。算例結果錶明，本文方法與實測值較為接近，且按本文方法求得的群樁中基樁相互作用繫數明顯小于彈性理論計算結果，且與實測值吻閤較好。
장군재토중적가근여차렴효응시객관존재적，단목전적이론여실천균미능혹유효지고필해효응。기우전절변형법원리，재계산모일근장침강시，고필료기타각상린기장적존재대해장침강적절감，즉가근여차렴효응，득도료장측장－토접촉등효전절탄황강도，건립료장신위이미분방정，분별구득장정침강－장단침강、장정하재－장단압력적체추관계，종이득도료각장재자신하재작용하인기자신침강적유도계수；동리，야구득료각린장재기장정하재하인기타장침강적유도계수，최종건립료군장침강계산적유도구진방정。추도과정중，고필료지기토적성층성급장단침강적상호영향，병제출료기우일정심도내적Mindlin 위이해차고필장경영향적장단압력－장단위이관계신모식。산례결과표명，본문방법여실측치교위접근，차안본문방법구득적군장중기장상호작용계수명현소우탄성이론계산결과，차여실측치문합교호。
The reinforcing and restraining effect of piles embedded in soils is objective.However,this effect is not or has not been effectively considered in the present theory.The relevant research work needs to be continued. Based on the shear displacement method,the reinforcing and restraining effect is taken into account in the calculation of the pile group settlements in this paper.The reduction effect caused by the existence of the other adjacent piles and the equivalent stiffness coefficients of soil around each pile are developed.Then on the basis of the shear deformation transfer method,vertical displacement equation caused by load acting on top of the analyzing pile is built.So recurrence relations of settlement and axial force between pile head and pile tip are respectively deduced.Thus a flexibility coefficient of the displacement at the pile top induced by its load is obtained. Meanwhile,the flexibility coefficients for the piles due to the loads of adjacent piles are also gained.Lastly,a flexibility coefficient matrix equation is built to calculate settlement of pile groups with high or low pile caps.On the process of the deducing,the multilayer of soils and the interaction of settlements between piles bases are taken into consideration.A new relationship between pile-end resistance and pile-end settlement is proposed using Mindlin displacement solution.Comparisons of the settlement calculation for two pile cases are given to demonstrate the effectiveness and accuracy of the proposed method.The calculating interaction coefficients are much less than the elastic theory methods.
