桩

By means of field test for the pile of 15 meters length and MARC finite element analysis, this paper studies the bearing mechanism of the reinforced mixing pile, analyzes the law of load transfer and the percentage about cement-soil ring and reinforced concrete core under vertical load, analyzes the change law and interactive behavior about the pile's surface bearing and end bearing. In the end an experiential equation that can be used in Tianjin area to estimate the bearing capacity of single pile is proposed on the basis of test researches and finite element analysis.

分析了劲性搅拌桩在竖向荷载作用下的荷载传递规律及芯桩与水泥土的荷载分担比；分析了劲性搅拌桩在竖向荷载作用下桩侧摩阻力和桩端阻力随桩顶荷载的变化规律；分析了劲性搅拌桩在竖向荷载作用下桩端阻力及桩侧阻力的发挥性状与桩土位移间的关系及端阻力与侧阻力的荷载分担比。

It proved that, when sum of piles, length of piles and diameter of piles were equal, effect coefficient of piles group per m^2 was at the maximum with quincunx laying-out piles, next rectangle and minimum square, the quincunx laying-out piles groups was a better choice than the others laying-out piles group in many eases.

计算表明，当桩数、桩长、桩径相同时，单位承台面积上的群桩效应系数，呈梅花形布桩的最大，呈矩形布桩的次之，呈正方形布桩的最小。因此，呈梅花形布桩群桩是较好的选择。

Vesic's solutions to cavity expansion that include cylindrical cavity expansion and spherical cavity expansion are introduced. Then cylindrical cavity expansion theory is applied to study compaction effect of pile driving in saturated soil. Based on the results of conventional triaxial tests, a trilinear curve model is used to simulate stress-strain curve of strain-softening materials. Meanwhile, trilinear curves are also used to simulate curves of volumetric strain, minor principal strain and major principal strain. By using elasto-plastic theory, analytical solutions to cylindrical cavity expansion in strain-softening soil are presented. According to the mechanism of statically pressed pile driving, compaction effect of pile tip can be viewed as hemispheric cavity expansion. Therefore spherical cavity expansion theory is applied to obtain the solutions to stress, strain, displacement fields and final pressure. Resistance force of pile tip is calculated to estimate static pressure.

介绍了Vesic关于圆孔扩张问题的解答，其中包括柱形孔扩张问题和球形孔扩张问题，并应用柱形孔扩张理论分析了饱和软土中的沉桩挤土效应问题；在常规三轴试验成果的基础上，采用三折线模型模拟具有应变软化性质的岩土材料的应力应变关系曲线，分析了在应变软化土体中沉桩时桩周土的位移场、应力场和应变场的变化，得到了解析解答；分析了静压桩的沉桩机理，并利用球形孔扩张理论，视桩端处的挤土为半个球形孔的扩张，分析了桩端处土的位移场、应力场和应变场的变化，并根据最终扩张压力计算出沉桩时的桩端阻力，可作为压桩力的估算。

By using wave mechanics , the process of impact driving pile is analyzed,and a mechanics mode of impact driving system which consists of hammer spring cup and pile is established.

应用波动力学分析了冲击沉桩过程，建立了由冲锤、桩帽和桩组成的冲击沉桩系统的力学模型，研究了冲锤重量、桩帽刚度和桩波阻抗对效率的影响，在此基础上，提出了冲锤、桩帽和桩的最佳方案。

Model test shows that when raft is the principal bearing element, a single pile with cap has nearly the same behavior with a corresponding unpiled raft when subjected to vertical load. When the load acting on the pile cap exceeds the ultimate pile load, the pile carries less load than it's ultimate pile load. When the load exceeds 2 times of the ultimate pile load, pile is nearly at full capacity.

一、进行了室内模型试验，证明当以桩间土为主承担荷载时，带台单桩的荷载～沉降特性与天然地基上浅基础类似；当外荷载超过单桩极限承载力时单桩并不达到极限承载力，当外荷载超过2倍单桩极限承载力时桩顶反力才接近单桩极限承载力；此后加载台下单桩以接近极限承载力的状态继续承担外荷载。

The article analyses the relationship between the load of pile in the direction and the pile root.The investigation indicates that the carrying capacity has nice adaptability to the soil floor depth the column knocked into and change of the oil floor construction when the plinth depth is larger than 60cm,and the length of the column and the change of the soil floor have little impact on load of pile,whereas load of pile is more sensitive to the anti-sinking and change of column diameter dimension.

分析了基桩竖向承载力与桩体结构的关系，研究表明：承载力在基桩深度大于60cm后对桩体打入土层深度、土层结构变化有良好的适应性，桩长和土层结构的变化对基桩承载力的影响不大，而基桩承载力对止沉盘和桩径尺寸变化敏感。

The results indicate that when soil and pile are same, the shear stresses between pile and soil under the ultimate situations of different modes are different; the negative friction on pile induced by surcharge is maximum; and the negative friction of uplift pile is minimum; the friction of pile top induced by pressing pile and bottom-loaded pile is between them.

结果表明，同种土体和桩体条件下，各种模式达到极限状态时桩－土间剪切应力不同，堆载作用下负摩擦力值最大，抗拔桩负摩阻力值最小，桩顶受压桩、托桩的摩阻力值介于其间；桩材泊松比在0.15~0.35范围内时，桩侧摩阻力随泊松比的增大而增大。

In this paper, the feasibility of pile with high bearing capacity, such as post-grouting bored concrete pile, pedestal pile, huge pile and so on, used in top-down construction is studied. The construction speed increase of structure above ground i...

本文研究将高承载力的桩基，如桩端后注浆钻孔灌注桩、扩底桩、巨型桩等，在软土地区全逆作施工中应用的可行性；分别对于一柱一桩和一桩多桩两种逆作施工竖向承载体系，论证了高承载力的桩基的应用可以加快上部结构施工；总结了全逆作施工中的关键施工技术，如立柱的不均匀沉降、梁柱板墙的节点、一柱多桩的转换梁板等；提出了软土地区高层建筑全逆作施工总体方案制定应遵循的一些基本原则，如主楼群房的逆顺组合、全逆作的逆顺分界选择、挖土方式选择等。

Furthermore, authors statistic actual impacting times in the local by various types of hammer when the pile drives into the different depth of the bearing stratum, it may offer the reference for the similar engineering to choose the hammer in the future.

因此，如何对该类型的桩进行合理沉桩分析，是桩基施工中急待解决的问题。 2沉桩阻力在沉桩施工的过程中，桩锤的冲击力应大于土层的沉桩阻力，桩才能顺利下沉。

At the same time, the finite staff element method is used to analyze the influence of beam rigidity; and the two new methods proposed are used to analyze the influence of connect way between piles and beam; and the conclusion is obtained that the rigidity ratio between beam and piles being 0.48 is appropriate; the continuative increase of the rigidity ratio is not significant; the worst condition is that connecting way between piles and beam is hinged; the best condition is that connecting way between piles and beam is rigid. Whether is single-row pile or are double-row piles, when the front of single-row pile or the front of the front-row pile(in the double-row piles) needed excavation, it is supposed to that ought to be carefulness to excavate, because it is that the engineering cost increased greatly.

同时，用有限杆单元法，对双排桩的连梁刚度和用文中提出的方法以桩梁连接方式进行了试验和理论分析得出如下结论：在满足不相互影响排桩间距的情况下，桩顶连梁与桩的刚度比不小于0.48是合适的，此时再增加连梁刚度无意义；桩梁连接为铰结时双排桩受力变形性质最差，刚结时受力变形性质最好；不论是单排桩还是双排桩，桩前和前排桩桩前土体需要开挖时应慎重，因为这种开挖对支护结构影响很大，造价增加很多；双排桩省钱，而且抵抗变形的能力强，值得在工程中研究和广泛应用

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。