岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2014年
10期
2875-2880
,共6页
桩筏基础%模型试验%筏板刚度%承载特性
樁筏基礎%模型試驗%筏闆剛度%承載特性
장벌기출%모형시험%벌판강도%승재특성
piled raft foundation%model test%raft rigidity%bearing characteristic
梁板式桩筏基础作为新型风机基础,前景广阔,适当优化结构,可节约成本。采用大型室内模型试验,研究了梁板式桩筏基础在不同筏板刚度情况下的受力变形特性,同时讨论了桩土荷载分担比的关系。研究表明,在工作荷载范围内,适当增大筏板刚度,桩平均轴力增加,外圈桩承担的荷载增大,内圈桩的轴力减小,环梁及肋梁弯矩减小,但继续增加刚度,对桩身轴力、环梁弯矩、肋梁弯矩的影响并不大;随着荷载的增大,土体承担的荷载比逐步增大,趋于稳值。随着梁板式基础刚度增加,基础内外差异沉降减少,但是达到一定刚度后再增加刚度对变形影响较小。梁板式基础刚度的变化会影响基底反力分布的均匀性,且存在一个最优刚度,使基础底部反力分布最为均匀,本次试验中12梁的梁板式基础基底反力比6梁和实体基础更均匀。桩基的分布和梁的分布存在相互影响,改变梁的分布会影响桩顶力,而桩基在梁底下又会使梁的应力产生重新分布。研究成果可为设计桩筏基础提供参考依据。
樑闆式樁筏基礎作為新型風機基礎,前景廣闊,適噹優化結構,可節約成本。採用大型室內模型試驗,研究瞭樑闆式樁筏基礎在不同筏闆剛度情況下的受力變形特性,同時討論瞭樁土荷載分擔比的關繫。研究錶明,在工作荷載範圍內,適噹增大筏闆剛度,樁平均軸力增加,外圈樁承擔的荷載增大,內圈樁的軸力減小,環樑及肋樑彎矩減小,但繼續增加剛度,對樁身軸力、環樑彎矩、肋樑彎矩的影響併不大;隨著荷載的增大,土體承擔的荷載比逐步增大,趨于穩值。隨著樑闆式基礎剛度增加,基礎內外差異沉降減少,但是達到一定剛度後再增加剛度對變形影響較小。樑闆式基礎剛度的變化會影響基底反力分佈的均勻性,且存在一箇最優剛度,使基礎底部反力分佈最為均勻,本次試驗中12樑的樑闆式基礎基底反力比6樑和實體基礎更均勻。樁基的分佈和樑的分佈存在相互影響,改變樑的分佈會影響樁頂力,而樁基在樑底下又會使樑的應力產生重新分佈。研究成果可為設計樁筏基礎提供參攷依據。
량판식장벌기출작위신형풍궤기출,전경엄활,괄당우화결구,가절약성본。채용대형실내모형시험,연구료량판식장벌기출재불동벌판강도정황하적수력변형특성,동시토론료장토하재분담비적관계。연구표명,재공작하재범위내,괄당증대벌판강도,장평균축력증가,외권장승담적하재증대,내권장적축력감소,배량급륵량만구감소,단계속증가강도,대장신축력、배량만구、륵량만구적영향병불대;수착하재적증대,토체승담적하재비축보증대,추우은치。수착량판식기출강도증가,기출내외차이침강감소,단시체도일정강도후재증가강도대변형영향교소。량판식기출강도적변화회영향기저반력분포적균균성,차존재일개최우강도,사기출저부반력분포최위균균,본차시험중12량적량판식기출기저반력비6량화실체기출경균균。장기적분포화량적분포존재상호영향,개변량적분포회영향장정력,이장기재량저하우회사량적응력산생중신분포。연구성과가위설계장벌기출제공삼고의거。
As a new foundation for wind turbine on land, piled beam-slab foundation has a broad prospect .The optimized structures properly can reduce costs. To investigate the bearing and deformation characteristics of piled beam-slab foundation under vertical loads under different raft rigidities, a large-scale model test is carried out, which also research the ratio of the force carried by pile and that carried by soil. The research shows that within the range of work load, average pile axial force increases with the increase of the raft rigidity;the axial force of the outer-ring-piles increases while the axial force of inner-ring-piles reduces. The moment of the ring beam and the ribbed beam decrease when the rigidity continues to increase after a certain value, there is little effect on axial force, moment of the ring beam and ribbed beam. With the increase of the stiffness of the beam-slab foundation, the differential settlement of the foundation decreases. However, this trend will become insignificant as the stiffness increases to a certain value. The variety of rigidity of the piled beam-slab foundation could make a difference on the uniformity of subgrade reaction. Besides, there is an optimal stiffness that can make the foundation reaction distribution most uniform. In the experiment, the subgrade reaction distribution of the piled-beam-slab foundation with 12 beams is more uniform comparing to the foundation with 6 piles and block foundation. And there is an optimal rigidity for piled beam-slab foundation, which makes the soil beneath the foundation beared more loads while piles do less. The distribution of piles and beams produces mutual effects on each other. When the distribution of beams changes, the forces of the pile top will be affected. And piles under the beams will also result in beam stress redistribution. In actual project, the rigidity of caps should be optimized and the research results can provide reference for the design of piled beam-slab foundation.