灌注桩施工质量通病的防治

混凝土和钢筋混凝土灌注桩工程施工时,经常发生一些质量通病,本文结合这些质量通病,提出预防措施和处理方法。     

麦饭石对诱导星晨花试管嫩梢生根的影响

在星晨花培养基中加入不同浓度的麦饭石，以达到缩短培养周期和改进培养质量之目的，试验结果表明，加入５％浓度的麦饭石在促进星晨花苗提早生根、提高组培苗的质量上表现最佳．     

多年冻土地区钻孔灌注桩回冻初期承载力的计算

多年冻土地区钻孔灌注桩在施工过程中产生的各种热量引起了桩周冻土一定范围升温及融化，本文按照桩周冻土颗粒的不同，编制Visual Basic6．0程序计算桩周融土压力，从而计算回冻初期单桩承载力。所得结果与按照铁路桥涵与公路桥涵规范公式计算结果对比。并结合工程实例对多年冻土地区的钻孔灌注桩回冻初期的单桩承载力进行了计算分析。所得结论可为多年冻土地区桥梁工程施工计划的制定提供参考。     

JK270+688大桥挖孔桩施工技术

结合所在地的实际情况 ,经施工方案比较 ,采用挖孔桩方案。并着重介绍了施工工艺 ,困难地段处理及混凝土的灌筑。施工中全方位控制施工的各个环节 ,实践证明 ,该方法是一种可操作性强、并对质量控制措施有效、可行的方法。     

水泥搅拌桩的设计、施工及检测

对水泥搅拌桩在设计、施工、检测等方面作了全面阐述,并且提出了若干注意事项及合理化建议。     

A Summary of Resesrch State on ProtectingAncient Stone Carvings from Weathering

It is a problem difficult to solve in the world to protect ancient stone carvings from weathering.In this paper,the research state of protecting stone csrvings beaten in the open is summarized and discussed. In the print of seriously weathered stone carvings on the rock wall in the open, some new research method is proposcd, especially, hydrologic- geochemical reaction and weathered rock carvings due to subsidence of rainwater and groundwater permeation.     

LITHOLOGICAL CHARACTERS OF CARVED SANDSTONE IN DAZU

The carved sandstone of Dazu county in Sichuan is a stratum under the Pen-laizhen group of late Jurassic. This sandstone is similar to seme typical character of arkcoe in compo-sition and structure of the corrosive cementation. The weathered damage of the carved stone art hasa relation to degenerative after-change process of sandstone.     

A CASE STUDY OF COMPOUND FOUNDATION SUPPORTED BY SAND AND OVAL STONE PILES

This paper describs a case study of foundation engineering for forming sand and oval stone piles through the action of quaking, water striking,pouring and packing by a pile driver. The piles and packking mud are combined, forming a compound foundation to support the upper loads. This paper introduces the design and construction of this engineering. In order to check this method for consolidating the soft foundation,the loading test and the settlement observation in site are made. After the construction work,there has been an organized technical identifying meeting. The result out of the identification is positive.     

Increase of Wave Velocity in Precast Pile along with Time and Its Analysis

Low strain dynamic testing on actual pile was conducted to investigate if the wave velocity is varied in the installed pre-cast pile.It was found that the wave velocity of the pile is raised along with time.The analysis has been carried out through with one dimension and three dimension stress wave propagation theories.Among various factors influencing the rise of wave velocity,the factor of the side soil contribution is the chief one.The soil around the pile works jointly with the pile,as if to enlarge the section size of the pile.Both the increase of wave velocity and the bearing capacity of pile are consistent.So the time effect of wave velocity can be used to study the time effect of bearing capacity of the pile and to determine the bearing capacity of piles.     

Dynamic Behavior of Geogrid Reinforced Pile Supported Embankments under Moving Load

In order to investigate the dynamic behavior of geogrid reinforced pile supported embankments (GRPS) under moving load, a three dimensional coupled mechanical and hydraulic model was built by FLAC 3D. The results from two cases including unreinforced and no pile embankments, and geogrid reinforced pile supported embankments were presented. The behaviors of vertical displacement, pile soil stress ratio, excess pore water pressure, and vertical acceleration under two cases were compared and discussed. Additionally, studies on the effect of speed and weight of the moving load were performed. It is indicated that the value of vertical displacement, pile soil stress ratio, excess pore water pressure, and vertical acceleration of GRPS decrease evidently compared with those of unreinforced and no pile embankment, which is caused by the soil arching effect and the reinforcement effect. It is also shown that the greater the axle load value is, the less the beneficial effect of GRPS on the vertical displacement. With the increase of the moving speed of the load, the vertical displacement increases.