Sinking of piles by impression

Theoretical and experimental investigations of the use of impressed piles to strengthen the beds of foundations of buildings and eliminate their dangerous settlement caused by errors in design and work production are presented. The high efficiency of this method is demonstrated. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 25–27, May–June, 1997.     

谈夯扩桩在高层建筑中的应用

本文通过三明建设大厦采用夯扩桩基的实例，试桩验证及建筑物最终沉降的观测分析认为：只要采用一些合理的施工工艺措施和严格的质量管理，锤击沉管夯扩桩应用于高层建筑的基础工程是可行的，且具有较好的经济效益。     

Swelling properties and coefficient of permeability of friction-reducing polymer for pull-out of temporary sheet piles

Harmful cracks and settlements occur after the pull-out removal of temporary sheet piles. This is because a large amount of soil is discharged from the ground due to the significant skin friction at the steel surface. In order to prevent these cracks and settlement problems, a friction-reducing polymer was developed. After a sheet pile coated with the polymer is installed into the ground; the polymer absorbs ground water and transforms to a swollen gel layer which separates the soil and the sheet piles. In this investigation, a newly designed column type test apparatus was used to simulate ground conditions. The swelling test was carried out, followed by a continuous permeability test. Based on the obtained test results, the swelling properties and coefficient of permeability of the friction-reducing polymer in the ground were determined. The main conclusions are as follows. The values of the water-absorbing ratio, Ra_max, decrease with increasing earth pressure, p′, independent of the pore water pressure, u. Equations to determine the values of Ra_max are proposed as functions of p′ only. The maximum swelling pressure, at which the friction-reducing polymer cannot absorb water and swell, is p′_max?=?560?kPa. Even at a depth of approximately 100?m, the polymer absorbs ground water, and the swollen gel layer forms. The approximate range of coefficient of permeability, k, of the swollen gel layer is 10^?13–10^?11 m/s; these are extremely small values. The swollen gel can be considered an impermeable material. Depth distributions of the thickness and the coefficient of permeability of the swollen gel layer are illustrated in practical charts, based on the test results.     

水力机械法下沉沉井

通过对某江边水泵房沉井施工的总结,论述采用水力机械法下沉沉井的施工方法和注意事项。     

时空效应原理在沉井中的应用

通过上海市富锦路地道雨水泵站沉井施工,介绍了原定湿沉成井改为干沉后,施工中采取的纠偏、封底等措施。着重阐述了软土工程中时空效应原理和在沉井工艺中的应用。经实践,沉井完全达标,对周围构筑物与管线没有影响,而且节约了1个月的施工期和40万元。     

用气囊进行过江管道沉管施工的工程实践

本文通过工程实例,介绍过江管道海上浮运、连接与沉放过程,对类似工程施工具有一定的借鉴意义.     

下沉式抗滑桩的设计

本文主要针对下沉式抗滑桩提出了简化计算方法,并以实际说明了在滑坡治理工程中采用下沉式抗滑桩有较显著的经济效益。     

沉管管桩贯入度的准确控制

结合工程实例,分析了影响沉管管桩贯入度的因素,介绍了沉管管桩贯入度施工设计方法并与实际控制结果进行了比较。提出了提高贯入度控制准确性的实用方法。     

大桥加固过程中新桩对已有桩基影响研究

结合某桥梁加固工程实例,探讨了新桩施工与冲孔挤土对已有桩基的影响,分析了新桩施工过程中已有桩基弯矩承载力,得出了一些结论,为工程施工提供了依据。     

“T”形沉井的下沉施工技术

1 工程概况 浙江省温州市某污水处理厂工程位于温州市燕化镇桃花岛以南,蒲州河以东,团江西岸,该污水处理厂工程的粗格栅间及进水泵房采用沉井结构,该沉井平面形状为“T”形(见下图),其中“T”形的“-”部分为进水泵房,“I’部分为粗格栅间。 该沉井外包尺寸为30100×1933mm,“T”形肋宽为10900mm,面积约为400m~2;沉井进水泵房高度为     

Analysis of piles in rock

A review of research on the performance of piles in rock is presented. It is demonstrated that the bearing capacity of a pile is determined not only by the uniaxial compressive strength of the rock in its bed, but also by such factors as the ratio of the diameter of the pile to the depth of its embedment, the ratio of the compression modulus of the rock mass to the elastic modulus of the concrete pile, and the conditions at the contact between the lateral surface of the pile and rock, as well as procedural characteristics of the work performed in installing the piles. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 8–12, January–February, 2007.     

基桩高应变动力检测在工程桩检测中的应用

介绍了基桩高应变动力检测的测试原理，并引用工程实例加以阐述，通过对试验过程及其结果的分析证明，此法能够有效地补充和部分取代静载荷试验，在节约费用、提高效率的情况下还能很好地保证质量。     

Effects of existing piles on lateral resistance of new piles

Cyclic lateral-loading centrifuge tests were conducted on a new pile located at the center of 2×2 existing piles, to evaluate the effects of the existing piles on the new pile's lateral resistance when the piles of an old building are left derelict. Furthermore, two-dimensional FEM analyses of the horizontal cross sections of the pile–soil systems were carried out. The centrifuge test results show that the lateral resistance of a new pile, located among existing piles, shows slight increases. The existing piles increase the horizontal subgrade reaction of the upper part of the new pile, but slightly decrease that of the lower part of the new pile. Numerical analyses reveal that the key to whether an existing pile increases the horizontal subgrade reaction of a new pile or not, is the soil displacement at the location of the existing pile. An existing pile increases the horizontal subgrade reaction of a new pile when the existing pile displacement is less than the soil displacement caused by the new pile. Conversely, an existing pile decreases the horizontal subgrade reaction of a new pile when the existing pile displacement is greater than the soil displacement caused by the new pile.     

Bored compaction piles

Cast in-situ bored piles of a special type developed at the Central Building Research Institute, Roorkee, India, have proved particularly useful for loose soils with a high water table as well as in other situations. Their construction and applications are described in this article. Professor Mohan, who is Vice-President of CIB, is director of the Institute, where G. S. Jain is scientist co-ordinator and M. P. Jain is a research scientist.     

水泥搅拌桩

本文介绍地基处理的一种常见方法--水泥搅拌桩.采用水泥等材料作为固化剂,通过深层搅拌机械对淤泥、淤泥质土、粘土、亚粘土等进行深层搅拌,提高地基土承载力.     

MC劲性复合桩与钻孔灌注桩在某工程项目中应用对比分析

MC劲性复合桩具有高承载力、低压缩性等优点.相较于常规钻孔灌注桩,MC劲性复合桩在一些淤泥、淤泥质土、含砂土或粉土较多土层较厚的土质,有很强的适应性和经济优势.本文主要介绍一实际工程项目上MC劲性复合桩与灌注桩应用对比研究结果,通过试桩及静载检测结果对比分析了两种桩型在该项目上的优劣和适用性.MC劲性复合桩环境污染小,造价较低,施工质量可靠、施工简便、施工速度快,单桩承载力较高,同时大幅度改善了桩间土的软弱状态和承载力参预度等优点,具有较高的经济效益与社会效益.本文提出了施工中应采取的措施及注意事项,并展望了 MC劲性复合桩在未来地基基础中的应用前景.