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Search Results: 1 - 10 of 44655 matches for " 齐昌广 "
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塑料套管混凝土桩加固公路软土地基现场试验研究
左殿军,广,张宇亭,刘晓强
岩石工程学报 , 2013,
Abstract: 根据某一高速公路塑料套管混凝土桩加固软土地基工程实例,对桩土应力、地表沉降、横向位移、不同深度孔隙水压力进行观测,讨论了塑料套管混凝土桩桩承式路堤的工作机理。结果表明:塑料套管桩加筋路堤的临界高度约为1.26倍桩净距,观测期末,荷载分担比接近89%;桩帽和桩间土最大差异沉降为30mm左右,且应力集中比随着差异沉降的增大而线性增大;路堤堤脚附近不同深处横向位移随着路堤填筑高度的增加而增加,施工结束时,地表以下2.5m处横向位移最大,为12.86mm;横向位移-沉降比和横向位移增加率随着路堤填筑高度的增加逐步减小并趋于稳定,塑料套管混凝土桩加筋路堤系统能够有效防止路堤横向位移的发展和改善路堤的整体稳定性。
双向循环荷载作用下码头群桩基础受力特性数值分析
左殿军,陈龙,田志伟,广
岩石工程学报 , 2015,
Abstract: 依据天津某液化天然气接收站码头工程,采用abaqus有限元软件研究了码头全直桩基础在波浪和车辆双向循环荷载作用下的受力特性,讨论了循环周期对基桩受力特性的影响。结果表明:在竖向和水平向双向循环荷载作用下,基桩受力重新分布,桩身轴力逐渐变大,侧摩阻力减小,其中中排桩桩身轴力增加幅度最大;基桩侧摩阻力变化主要集中在1/3桩长以上范围;循环周期对基桩受荷分布产生较大影响,随着循环周期的变大,基桩受荷分布逐渐调整,前、后排桩桩身轴力逐渐变大,中排桩桩身轴力减小,排桩侧摩阻力均减小,当荷载循环周期达到一定值时,排桩的桩身轴力、侧摩阻力不再变化,趋于稳定。
塑料套管混凝土桩单桩承载特性研究
陈永辉,广,王新泉,陈龙
中国公路学报 , 2012,
Abstract: ?为研究塑料套管混凝土桩(TC桩)的承载特性,采用室内试验研究外设塑料套管对桩体竖向抗压强度的影响;结合现场试验,对不同桩尖类型的桩体进行了静载和荷载传递试验,分析不同桩尖类型的TC桩单桩承载能力和桩身轴力、侧摩阻力及端阻力的变化规律。建立了TC桩单桩沉降和侧摩阻力的简化计算方法,并与现场实测数据进行了对比。试验结果和理论分析结果表明:外设的塑料套管可提高桩身混凝土的竖向抗压强度约23%~38%;桩尖直径为26cm圆形桩尖的单桩静载试验的极限承载力最大,其次是30cm圆形桩尖、方形桩尖、十字形桩尖;侧摩阻力沿桩深呈两头小中间大的态势,最大侧摩阻力发生在2/5~4/5桩深范围内;所得的理论值与实测值相吻合。
路堤荷载下y形桩与常规桩型对比研究
王新泉,陈永辉,陈龙,广
铁道工程学报 , 2011,
Abstract: ?研究目的:利用abaqus有限元分析软件,建立y形桩、圆形桩和方形桩三种桩型的有限元计算模型,桩采用弹性模型,土体采用mohr-coulomb弹塑性模型。在相同布桩方式和相同面积置换率工况下,研究在路堤荷载分级加载过程中,三种桩型的盖板顶沉降、桩间土沉降、盖板顶和桩间土差异沉降、盖板顶平均应力、桩底平均应力等的变化规律。研究结论:通过对比得知:在相同荷载作用下,圆形桩盖板顶产生的沉降最大,其次为方形桩、y形桩;圆形桩桩间土产生的沉降最大,方形桩前期大于y形桩,之后又小于y形桩;盖板顶与桩间土差异沉降基本呈现圆形桩最大,其次为y形桩、方形桩;盖板顶和桩底平均应力,呈现方形桩最大,其次为圆形桩、y形桩。
塑料套管管侧前注浆桩承载特性的现场试验研究
广,刘干斌,陈永辉,郭卫
岩土力学 , 2015,
Abstract: 为提高塑料套管混凝土桩(简称tc桩)的承载性能,结合桩侧注浆技术,发展和形成了塑料套管管侧前注浆桩(简称tcsg桩)。通过现场试验,对tcsg桩、tc桩和扩径塑料套管混凝土桩(简称tcld桩)3种桩型在不同时期进行了静载试验,并引入了3种易于应用的单桩沉降计算模型对各桩体的沉降进行了计算。试验结果和沉降模型计算分析表明:与tc桩相比,tcsg桩增加了8.3%~20.0%的承载力,并减小了19.8%~33.5%的沉降,而tcld桩降低了10.0%~16.7%的承载力,且增加了13.2%~43.8%桩体的沉降;tcsg桩的轴力衰减速率大于tc和扩径的tcld桩的,tcsg桩的前、后期的平均轴力衰减速率相差不大,tc桩后期的平均轴力衰减速率相比前期提高了1.1%~14.2%,而tcld桩却降低了5.9%~21.9%;在前、后期静载时,tcsg桩在各级荷载下的平均单位侧摩阻力相比tc桩分别提高了14.5%~39.6%和9.2%~28.6%,扩径后的tcld桩则分别降低了4.9%~11.8%和11.5%~30.7%;管侧前注浆后的tcsg桩的时效特性不显著,扩径后的tcld桩的侧摩阻力随时间减小而端阻力则增大;基于桩土荷载传递的单桩沉降计算模型能够较好地预测塑料套管桩的沉降。
利用人工合成透明土的岩土物理模拟试验
广,范高飞,崔允亮,张强
岩土力学 , 2015,
Abstract: 结合粒子图像测速(piv)和近景摄影技术,建立了一种利用人工合成透明土的岩土物理模拟试验方法,非侵入观测和记录了浅基础沉降(sfs)引起的土体变形,并与利用天然土的传统模型试验进行了对比研究。透明土是由与熔融石英的折射率相匹配的孔隙溶液组成。采用激光面照射透明土模型并拍摄下sfs引起变形的数字图像,利用基于matlab的geo-piv软件获得了所产生的位移场。试验结果对比分析显示:与天然砂土中的相比,在透明土中sfs引起的扰动区域较大,最大剪应变扩大了约1.5倍,表层隆起范围约增加了30~50%;然而透明土中土体单元的运动趋势总体上与天然砂土中的相似,表明所建立的试验方法在机制研究上具有一定程度的适用性。
桩承式加筋路堤格栅应变计算及试验
Calculation and test of geogrid strain in pile-supported reinforced embankment

陈永辉,陈庚,广,徐锴
- , 2016,
Abstract: 为了完善桩承式加筋路堤中土工格栅应变的计算方法,在德国规范EBGEO的基础上,考虑桩帽及土工格栅刚度对格栅应变计算的影响,提出考虑等效桩径系数的修正计算方法,同时依托桩承式路堤现场试验,监测记录了路堤沉降、桩土压力和格栅应变的变化规律,并将实测结果与计算结果进行了对比。研究结果表明:格栅类型对路堤填筑期沉降影响不显著;桩土间的荷载传递随着格栅模量的增大而得到进一步加强;路堤荷载传递形式因采用不同类型的格栅而存在差异;填筑期内钢塑格栅应变随路堤填筑高度的增大而增加,且观测到了徐变性;钢丝格栅在填筑期内的应变变化不明显,但在填筑期结束后观测到了应变突变现象。通过现场试验与理论计算结果的对比,验证了采用等效桩径系数法计算格栅应变的合理性,并建议当采用钢丝格栅等高强刚度格栅时,可采用考虑等效桩径系数的修正EBGEO法进行格栅应变与应力计算。
In order to improve the calculation method of geogrid strain in pile-supported reinforced embankment, this paper based on the German standard EBGEO, considered the effect of cap and the stiffness of geogrid on the calculation of geogrid strain and proposed the modified calculation method with consideration of equivalent pile diameter. Based on field experiment of pile-supported embankment, the embankment settlement, pile-soil stress and the rule of the geogrid-strain variation were monitored and recorded, and the measured results were compared with the calculated results. The results show that types of geogrid have no significant effect on embankment settlement. Pile-soil load transformation is further strengthened with the increase of modulus of geogrid. There are differences in the transformation mode of the embankment load. Strain of steel-plastic geogrid increases with the increase of the height of embankment in the filling period, what’s more, creep is observed. The strain changes of wire geogrid during the filling period are not obvious, but strain mutation appears after that. By comparing the field experiment results with the theoretical results, the rationalization of the equivalent pile diameter coefficient method used to calculate the geogrid strain is verified. It is suggested that the modified EBGEO method with consideration of the equivalent pile diameter coefficient can be adopted for geogrid strain and stress analysis when the high-strength stiff geogrids such as steel geogrids are used
利用透明土模型试验的细长桩压曲研究

张婉璐,陈永辉,广
- , 2016,
Abstract: 为了研究细长单桩和多桩在竖向荷载作用下的压曲变形以及非介入性地测量细长桩屈曲 引起的土体变形,利用透明土模型试验并结合粒子图像测速(particleimagerelocimetry,PIV)技 术,成功地对不同长宽比以及不同桩数细长桩的屈曲过程进行了试验研究。采用激光照射透明土 形成散斑场,并采用单反相机拍摄关心区域的数字图像,利用PIV 技术分析图像所获得的位移场。 研究结果表明:单桩情况下,桩上下端发生反方向的屈曲变形;多桩条件下,桩下部存在一定的嵌固 深度,上部桩身弯曲形式为半个周期的正弦函数;随着长宽比的增加,产生最大横向位移的点不断 上移,但是对上半部分桩屈曲变形的范围影响不大;无论在单桩还是多桩条件下,下部土体的水平 抗力大于上部土体,从而导致了最大横向位移发生在桩的上半段。
塑料套管混凝土桩的承载力时间效应研究
广,陈永辉,王新泉*,*刘干斌
岩石工程学报 , 2015,
Abstract: 在塑料套管混凝土桩(tc桩)成桩机理的基础上,采用圆柱扩孔回缩理论和径向固结理论预测tc桩施工引起的桩周土超净孔压的消散,建立了tc桩承载时效的理论计算方法。通过开展现场试验,对比研究了tc桩承载时效理论的合理性。结果表明:考虑桩周土的回缩的承载时效计算结果及其随时间变化的规律与实测值相吻合;而不考虑回缩时,不同休止期对应的承载力将被高估160%~300%。
桩承式加筋路堤土拱效应现场试验
Field test on soil arching in pile-supported reinforced embankment

陈 庚,陈永辉,徐 锴,广,蔡 锐
- , 2016,
Abstract: 为研究桩承式加筋路堤填土中竖向应力分布和土拱效应临界高度的变化规律,依托塑料套管现浇混凝土桩(TC桩)承式路堤现场试验,在填筑预压期对桩帽、桩间土及不同填土高度处土压力进行全过程监测,分析了路堤填筑及预压过程中桩土间的荷载传递规律,同时结合土拱设计高度计算方法,研究填土中竖向应力分布和土拱效应临界高度的变化规律,对多种土拱形式的假定进行了现场试验验证分析,并基于试验结果,开展了路堤土拱形成的参数讨论。研究结果表明:填土高度约达到0.5倍桩间距时,桩帽上压力实测值大于该处路堤荷载,且桩土应力比大于1,表明路堤载荷开始从桩间土向桩体转移,路堤内土拱初步形成;填土高度约达到0.9倍桩间距后,后续填土对桩间土压力变化影响较小,说明路堤已形成完整稳定的土拱;观测到的土拱等沉面的高度为1.2~1.5 m,大于德国EBGEO 规程计算值,小于英国BS 8006规范计算值;与滑动面为沿桩顶轮廓线向上的假定与应力扩散理论相比,路堤中竖向土压力分布趋势与圆形土拱假定计算结果相符,但试验所得土压力测量值仅为理论计算值的50%和30%。因桩承式加筋路堤中桩间土压力随其距桩的位置不同会有明显不同,故建议采用桩土应力比联合桩帽上土压力大小综合判定桩承式加筋路堤的土拱形成。
In order to research the vertical stress distribution in filling and critical height of soil arch effect, the stress of pile cap, soil between piles and fill at different height were monitored and recorded, on the basis of field test on plastic tube cast-in-place concrete pile (TC pile)-supported embankment, the load transfer during the periods of embankment filling and preloading was analyzed. Meanwhile, vertical stress distribution in filling and critical height of soil arch effect was studied, assumptions about the soil arch was compared with the test results. Based on the experimental results, parameters of embankment soil arch were also discussed. The results show that the pile-soil stress ratio is more than 1 and the measured values of earth pressures on pile cap is bigger than the embankment load when the filling height of embankment approaches to 0.5 times of pile spacing, which indicates that embankment load begins to transfer from soils to piles and soil arching is initially formed. When height of the embankment is close to 0.9 times of pile spacing, the corresponding earth pressures in soils change little, which reveals that the complete and stable soil arching has been produced, the change range of soil arching root be carried as the reason. The measured height of equal settlement plane is between the calculated values of EBGEO and BS 8006. The monitoring of earth pressures in embankment demonstrates that soil arching is in a shape of semicircular. However, the measured values of earth pressures on pile cap and cushion are 50% and 30% of the calculated results from semicircular soil arching theory. Pile-soil stress ratio with the value of earth pressure on pile is suggested to judge the formation of soil arch in pile-supported reinforced embankment
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