【作者】 张良奇；

【导师】 查旭东； 孙太周；

【作者基本信息】 长沙理工大学 ， 交通运输工程， 2008， 硕士

【摘要】 CGMT(Cement Gravel Mixing Trenchless)非开挖干拌水泥碎石桩是在碎石桩、CFG桩基础上研发的新桩型,已应用于河南省高速公路病害处理和路基加固工程。由于地质条件以及CGMT桩的复杂性,目前对CGMT桩复合地基加固机理仍处于研究之中。本文通过理论分析、室内试验、现场试验等手段,对CGMT桩复合地基的加固机理及其优化设计理论进行了深入的研究。本文首先通过对CGMT桩复合地基改善松散砂土和软粘土地基的作用机理分析,认为CGMT桩主要通过振密挤密效应、置换效应、加速排水效应、垫层作用对地基进行加固。其次通过试验和分析,得出了CGMT桩的桩-土应力应变关系、桩土应力比、单桩和复合地基的承载力计算方法。通过对CGMT桩变形模式和机理的研究,表明桩体由加速排水效应改善了桩周土的微观结构,加速了地基填土的固结,减少了沉降。提出了合理的路堤荷载作用下CGMT桩复合地基的沉降计算方法,并分析了路堤沉降的影响因素。再次结合京珠高速公路许昌-漯河段CGMT桩加固工程实际,进行了大量的现场试验和室内试验,对CGMT桩处理地基的效果进行了检验,对复合地基的承载机理及应力应变机理进行了深入研究,最后通过地质雷达测试对加固效果进行了检验。论证了CGMT桩在高速公路路基加固中应用的可行性和优越性。最后对CGMT桩施工技术与质量控制和检测进行了详细的介绍。更多还原

【Abstract】 CGMT (Cement Gravel Mixing Trenchless) non-excavation dry mixing cement gravel pile is a new pile based on gravel pile, CFG pile, and also has been used in Henan Highway disease treatment and embankment reinforcement project. The mechanism of CGMT pile composite foundation reinforcement is still being studied at present because of the complexity of geological conditions and CGMT pile itself. It studies on its reinforcement mechanism and optimal design theory through the methods of theoretical analysis, laboratory experiment, in-situ experiment.Firstly, through the research of the reinforcement mechanism on loose sand foundation and soft clay foundation, the reinforcing effect of CGMT pile can be obtained through vibration and compaction effect, replacement effect, the accelerated drainage effect and cushioning effect. Through the experiment and the analysis, we have obtained the pile-soil stress-strain relations of CGMT pile, the pile-soil stress ratio, the calculation methods of bearing capacity of single pile and composite foundation.Secondly, according to the study on deformation mode and the mechanism of CGMT pile, we can see that the accelerated drainage effect accelerated the consolidation of the foundation filling and reduced the settlement by improving the micro-structure of the soil around the pile. We put forward a reasonable settlement calculation method under the embankment load, and analyzed the influencing factors of embankment settlement.Thirdly, we did a lot of in-situ and laboratory experiments based on the reinforcement project of Jing-Zhu highway Xuchang-Luohe section. We test the treating effect, take study on bearing mechanism and stress-strain mechanism of complex foundation. At last, the strengthening effect is tested by geologic radar. Its feasibility and superiority of embankment reinforcement in Highway has been validated.The end, this paper introduces the construction and quality controlling and test of CGMT pile.更多还原