铁道学报
鐵道學報
철도학보
2015年
2期
111-117
,共7页
群桩基础%计算模型%集中弹簧模型%分层文克尔弹簧模型%地震响应
群樁基礎%計算模型%集中彈簧模型%分層文剋爾彈簧模型%地震響應
군장기출%계산모형%집중탄황모형%분층문극이탄황모형%지진향응
pile foundations%computational model%concentrated spring model%Layered Winkler spring mod-el%seismic response
本文对群桩基础常用的抗震简化计算模型进行对比分析,指出各计算模型间的差异。在此基础上,提出改进的分层文克尔弹簧模型,并在该模型中采用桩身的等效面积比η间接考虑桩侧摩阻力和桩底土竖向抗力的影响。分析结果表明:应用集中弹簧模型模拟桩基础的柔性效应时,应考虑耦联刚度的影响;应用分层文克尔弹簧模型模拟群桩基础的桩土相互作用时,应考虑桩侧摩阻力和桩底土抗力的影响;在改进的分层文克尔弹簧模型中,桩身的等效面积比η随桩长及桩底土竖向地基系数的增加而增大,随桩径的增加而减小,且η值越大,对桥墩及桩基础的地震响应影响越大,只有当η接近1.0时,方可采用分层文克尔弹簧模型进行抗震分析。
本文對群樁基礎常用的抗震簡化計算模型進行對比分析,指齣各計算模型間的差異。在此基礎上,提齣改進的分層文剋爾彈簧模型,併在該模型中採用樁身的等效麵積比η間接攷慮樁側摩阻力和樁底土豎嚮抗力的影響。分析結果錶明:應用集中彈簧模型模擬樁基礎的柔性效應時,應攷慮耦聯剛度的影響;應用分層文剋爾彈簧模型模擬群樁基礎的樁土相互作用時,應攷慮樁側摩阻力和樁底土抗力的影響;在改進的分層文剋爾彈簧模型中,樁身的等效麵積比η隨樁長及樁底土豎嚮地基繫數的增加而增大,隨樁徑的增加而減小,且η值越大,對橋墩及樁基礎的地震響應影響越大,隻有噹η接近1.0時,方可採用分層文剋爾彈簧模型進行抗震分析。
본문대군장기출상용적항진간화계산모형진행대비분석,지출각계산모형간적차이。재차기출상,제출개진적분층문극이탄황모형,병재해모형중채용장신적등효면적비η간접고필장측마조력화장저토수향항력적영향。분석결과표명:응용집중탄황모형모의장기출적유성효응시,응고필우련강도적영향;응용분층문극이탄황모형모의군장기출적장토상호작용시,응고필장측마조력화장저토항력적영향;재개진적분층문극이탄황모형중,장신적등효면적비η수장장급장저토수향지기계수적증가이증대,수장경적증가이감소,차η치월대,대교돈급장기출적지진향응영향월대,지유당η접근1.0시,방가채용분층문극이탄황모형진행항진분석。
A variety of simplified seismic computational models mainly applied to group pile foundations were compared and then differences between them were pointed out . On this basis , an improved Layered Winkler spring model was put forward . The impact of lateral friction around piles and subsoil vertical resistance at pile tip was considered using the parameter ηin this model , which is equivalent area ratio of a pile . The results show that :The effect of the coupling stiffness should be considered when flexible constraint effect of pile foun‐dations was simulated by using concentrated spring model;The effect of lateral friction around piles and sub‐soil vertical resistance at pile tip should be considered when pile‐soil interaction of group pile foundations was simulated by adopting Layered Winkler spring model ;ηincreases with the increase of pile length and vertical foundation coefficient at pile tip , but decreases with the increase of pile diameter in the improved Layered Win‐kler spring model . The larger the ηvalue is , the greater the impact is on the seismic response of pier and pile foundation .Only when ηis close to 1.0 ,the Layered Winkler spring model can be used for seismic analysis .