灌浆锚杆在桩基处理工程中的应用

【作者】 周琦；

【导师】 彭振斌； 周安全；

【作者基本信息】 中南大学 ， 地质工程， 2002， 硕士

【摘要】 岩土锚固是岩土工程领域的重要分支。岩土锚固技术能充分调用和提高岩土体的自身强度和自稳能力，改善岩土体的应力状态，利用岩土体内部抗力增强结构物的稳定性，从而提高施工过程中的安全性。 锚固技术由于施工简便、经济、安全，从二十世纪初起被美国应用于煤矿顶板支护以来，几十年来无论在理论上还是在实践中都得到了很大的提高，国内外不少单位采用理论分析、模型实验、现场测试等分析方法为复杂地层的锚杆设计与施工提供了理论依据。同时国家和有关地区、部门颁布了相应的锚杆设计与施工规范。实践上的摸索与应用更有超前于理论的趋势。在我国边坡防治、桥梁、隧道、地下工程、矿井、基坑及抗浮、抗倾结构等工程领域得到了广泛的应用。发展到现在，已经成为提高岩土工程稳定性和解决复杂岩土工程稳定问题，减小嵌岩桩施工难度等最经济、最有效的方法之一。 灌浆锚杆是岩土锚固技术中最常用的锚杆类型之一，本论文结合龙荫港大桥桩基处理实例，利用锚固理论，以桩的剪切力和竖向承载力作为锚固力的设计值，在实践中大胆尝试采用钢轨作为锚杆的设计施工方法，充分利用桩基中钢轨本身的抗拉强度来达到设计承载力的目的，从而有效地减少整桩的嵌岩深度，改用在同一根桩中南大学硕上学位论文 中文摘要 2002 6基中用3－5根小锚固桩嵌岩的施工方法，减小了施工难度，增强了桩基在复杂地层中的稳定性；其次小钢筋笼应用于溶洞发育区的桩基加固，为增强抗弯抗扭起到了积极作用，尤其是小钢筋笼中钢筋的布置是沿四周分布，中间便于安装注浆管，为施工带来了方便。我们平常采用的锚杆通常设计为与水平方向夹角10－45”本次工程中考虑桩基主要是承受竖向剪切力，我们设计的锚杆与水平方向成9r 角，而且不需要承压板与锚头，同样可达到锚固的效果。由于在施工过程中我们采用的是灌浆锚杆，利用水泥浆液的充填、渗透、挤密作用达到扩底桩的效果，从而本次桩基处理方案合理、经济、安全，完全达到了预期的效果，对同类工程的设计与施工有一定的借鉴作用和指导性意义。更多还原

【Abstract】 Anchoring for soils and rocks is an important branch in the area of geotechnical engineering. The technology of anchoring for soils and rocks can fully transfer and raise the abilities of self-intensity and self-stability, improve the stress condition, enhance the stability of structure by using the inside-resistance of rocks-soils body, thus improve the security in the course of construction,The technology of anchor bar, because of easy, economic, and secure to construct, was using to hold the roof of coal mine from the beginning of twenties century. It gained a very big improvement on the theory and the practice for dozens of years. Many domestic and foreign companies use analytical methods of theoretical analysis, model experiment, field analysis, etc. to provide theoretical basis for anchor bar designing and constructing of complicated stratum. At the same time, our country and some region and department concerned have published relevant specification for anchor bar designing and constructing. Fumble and use in practice have a tendency to exceed the theory. In our country, the technologies of anchor bar have a wide using in the area of slope treatment, bridge,tunnel, underground-project, mine, foundation pit and the structure of resistance to buoyancy and inclination, etc. Developed to present, it become one of the best ways of economic and effective in improving the stability of geotechnical engineering, solving the problem of stability in complicated geotechnical engineering, and decreasing the construction’ s difficulty of the built-in piles.Grouting anchor bar is one of types of anchor bar, which is most in use in the technology of anchoring for soils and rocks. This paper is in the light of the example of pile foundation disposal of the Long Yin Gang Bridge. First, it uses the theory of anchoring and takes the shearing stress of piles as the designed value of bolt-locking force. We have a bold try in the practice by using the designing and constructing way of taking steel rails as anchor bars. This way can fully use the resistance-extension intensity of steel rails attaining the goal of designed bearing capacity. It can decrease the built-in depth effective. It can decrease the construction’ s difficulty and enhance the stability of pile foundation in the complicated stratum through the way of using three to five small anchoring piles in the same pile foundation. Second, the small steel bar cage was used to strength the pile foundation in the area of Karst cave developed. It can play a positive role in enhancingthe bending-resistance and torsion-resistance. Especially, it can make things convenient for construction because the steel bar’ s arrangement in the cage is distributed over all around, and is easy to install the pouring piles at the center. The separation angle of anchor bar and horizontal line was generally designed to ten to forty-five degrees. But in this project because pile foundation mainly bear vertical pressure, the separation angle of anchor bar and horizontal line was designed to ninety degrees. And the pile foundation was designed to have no bearing plate and anchorage. It can achieve the same results. We use grouting anchor bar in the construction, and take the role of filling, penetrating, compacting of cement grout to achieve the club-footed pile’ s result. So the plan of pile foundation disposal is reasonable, economic and secure. It fully achieves the desired results. It plays a certain reference and guidance roles to the designing and constructing of the similar project.更多还原