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141.
This study has evaluated the vertical bearing capacity by conducting static load tests for noise-free and vibration-free screw pretensioned spun high-strength concrete (PHC) piles installed using two different methods (end-squirting shoe and pre-boring methods). Vertical bearing capacity differences seem to occur due to the displacement of soils near the external circumference of a pile, depending on the installation method. A method by which to evaluate the bearing capacity of screw concrete piles is suggested by considering the equations that already have been used to calculate the bearing capacity of piles. Based on static load tests and analysis, the pile installed using the end-squirting shoe method was assumed to be a bored pile and it was reasonable to use the equation proposed by the Japanese Geotechnical Society. At the same time, the pile installed using the pre-boring method was deemed a low soil displacement pile and so it was reasonable to apply the equations proposed for calculating the bearing capacity of the driven pile suggested by the Architectural Institute of Japan. 相似文献
142.
The pile-driving method produces considerable noise and vibrations. Hence, an auger-drilled pile method was developed as a low-noise and -vibration substitute. However, this method does not guarantee the bearing capacity of the pile unless some amount of pile-driving is performed. Therefore, the noise and vibration problems cannot be completely solved. In this study, a prebored screw pile method is proposed to solve these problems. In this method, piles are constructed by the rotary penetration of a screw pile into a prebored hole filled with some cement milk and whose diameter is smaller than that of the screw pile. To determine the shape of the screw pile, laboratory tests with model screw piles were conducted. Also, field load tests were conducted on an actual screw pile fabricated based on the laboratory test result and on a smooth-surfaced pile. In addition, the behavior of the screw pile was estimated by using three-dimensional finite element analysis. The results of the field load test and the numerical simulation showed that the ultimate bearing capacity and the unit skin friction of the screw pile are very superior to those of the smooth-surfaced pile and the cement milk is an important factor in the prebored screw pile method. 相似文献
143.
为提高红河油田水平井固井质量,满足后期分段压裂需求,对红河油田水平井固井技术进行了研究。针对红河油田水平段固井技术难点,通过室内和现场试验,优选出了GSJ水泥浆体系,基于实测地层压力与地层破裂压力,进行平衡压力固井设计确定了环空浆体结构,为提高顶替效率,优化了扶正器类型与加放位置,专业软件模拟表明套管居中度>73%,良好的井眼准备和套管漂浮措施确保了管柱的顺利下入;加长胶塞、树脂滚轮刚性旋流扶正器和关井阀等附件的使用,保证了固井质量。现场应用53口水平井,水泥浆全部返至地面,CBL测井结果表明,固井优良率达81.13%。该固井技术成功应用于红河油田水平井中,保证了固井质量,满足了后期分段压裂的需要。 相似文献
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上海市东方医院(同济大学附属东方医院)青岛分院桩基工程,工程量大,工期紧,因上部存在填土、淤泥质土,地层条件较复杂。根据工程实际情况采用了旋挖钻机、冲击钻机、回转钻机成孔工艺,采取加长钢护筒、泥浆护壁等技术措施,有效解决了缩径、孔壁坍塌问题,保质保量按期完成了施工任务,取得了很好的经济和社会效益。 相似文献
148.
为保证泥浆护壁成孔灌注桩后注浆技术正确应用,首先分析了后注浆技术对泥浆护壁灌注桩的作用机理以及天津地区的应用现状,然后通过对影响其应用效果的多种因素,如从业人员资格、成孔成桩质量、注浆阀、注浆泵、注浆相关参数等分析研究,提出相应的措施或建议。 相似文献
149.
阜阳华纺新天地桩基工程,原计划基坑底面施工调整为地面施工,增加了近14 m的空桩。为此,工程桩施工质量存在桩位、孔底沉渣厚度、钢筋笼位置、砼质量、砼桩顶标高等方面控制的相关问题。本文介绍了其施工情况,其经验可供类似工程借鉴。 相似文献
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