Jingwei Zhang , Zhencai Luo , Yunlong Liu , Bowen Zheng , Zhenguo Hou , Jin Kong
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引用次数: 0
Abstract
Due to merits of low noise and vibration, the pre-bored planted method has been widely used in engineering practice to assist the installation of the prestressed high-strength concrete (PHC) piles in area where deep and thick sand layers are commonly encountered. However, the research on the influence mechanism of pile driving methods in hard soil layers mainly focuses on the static pressing method and the hammering method, while the penetration characteristics under pre-bored assistance remains unclear. Therefore, a full-scale field test was conducted to investigate the installation effects. The penetration mechanisms of the piles with pre-bored assistance in areas with a deep and thick sand layer was discussed. Besides, an analytical method was proposed to predict the energy (hammer blow counts) necessary to drive pile to design depth. The results showed that the pre-bored grouted planted method significantly reduced the energy required for pile driving, compared to both the hammering method and the pre-bored planted method. This was because pre-drilling reduced displaced soil volume and relieved lateral stress. The pile load transfer mechanism was optimized by pre-drilling, which effectively leveraged the high compressive strength of the deep and thick sand layers. Meanwhile, the shaft friction within the grouted depth was significantly enhanced by the permeation, cementation and reinforcement effects of the concrete slurry, thereby improving the pile bearing capacity. Furthermore, the analytical method proposed based on the cavity expansion theory was capable of predicting the energy required for pile driving, which could guide the selection of pile driving equipment with minimum energy consumption and prevent pile damage caused by excessive hammering.
期刊介绍:
Soils and Foundations is one of the leading journals in the field of soil mechanics and geotechnical engineering. It is the official journal of the Japanese Geotechnical Society (JGS)., The journal publishes a variety of original research paper, technical reports, technical notes, as well as the state-of-the-art reports upon invitation by the Editor, in the fields of soil and rock mechanics, geotechnical engineering, and environmental geotechnics. Since the publication of Volume 1, No.1 issue in June 1960, Soils and Foundations will celebrate the 60th anniversary in the year of 2020.
Soils and Foundations welcomes theoretical as well as practical work associated with the aforementioned field(s). Case studies that describe the original and interdisciplinary work applicable to geotechnical engineering are particularly encouraged. Discussions to each of the published articles are also welcomed in order to provide an avenue in which opinions of peers may be fed back or exchanged. In providing latest expertise on a specific topic, one issue out of six per year on average was allocated to include selected papers from the International Symposia which were held in Japan as well as overseas.