The Houhai area in Nanshan, Shenzhen, is a rising star in Shenzhen's commercial circles. Since the start of comprehensive construction in 2003, it has taken on a completely new look. In 2013, Houhai was included in the scope of Shenzhen's ten key recommended strategic development areas. Over the years, many Bauer rotary drilling rigs and hydraulic grabs have participated in the construction of urban rail transit projects and livelihood projects in the Houhai area.
Recently, five Bauer rotary drilling rigs belonging to Shenzhen Gongkan Geotechnical Group Co., Ltd. appeared at a construction site in Houhai, Shenzhen, to participate in a building foundation pile project. The project includes a total of 486 piles, with diameters of 1.0m, 1.4m, 1.8m, and 2.4m, and pile depths of over 30-60 meters. The main difficulties of this foundation pile project are:
1. Large rock-socketed depth and high rock strength
In addition to the variety of pile diameters, the pile depths are also relatively deep, and each pile generally needs to penetrate 2-5m into fresh moderately weathered or slightly weathered granite. According to the geological survey report, the uniaxial compressive strength of moderately weathered granite is 20-40MPa, and the strength of slightly weathered granite is 60-100MPa.
2. A single type of equipment cannot meet the construction requirements
A single small-sized equipment cannot meet the construction needs of large-diameter, deep piles, while a single large-sized equipment lacks economy when constructing small-diameter foundation piles. In response to the characteristics of this project, Shenzhen Gongkan Geotechnical Engineering Group Co., Ltd. leveraged its own advantages and deployed 5 Bauer rotary drilling rigs, including: 1 BG 25 rig, 2 BG 30 rigs, and 2 BG 38 rigs. The various models of Bauer rotary drilling rigs closely cooperate according to different pile diameters, pile depths, and rock-socketed requirements, leveraging their respective characteristics and maintaining steady and progressive output every day. In addition, the equipment's capability must meet the construction needs and maintain reasonable construction efficiency. After observing a pile with a diameter of 2.4m, a depth of 42.4m, and 2.5m rock socketing at the site, using a Bauer BG 38 rotary drilling rig, the required pure drilling time was about 18.0 hours. For the rock socketing in moderately weathered granite, the "two-stage" hole-forming method was adopted, and overall, the average rock-socketing efficiency remained stable at 0.32m/h.
4. Determining the rock surface of large-diameter foundation piles is relatively difficult, requiring high professional competence from the engineering team
For 2.4m large-diameter piles, the rock surface is often undulating, and whether the rock-socketed depth meets the design requirements is crucial to the quality of a pile. How to determine the starting position of the fresh rock surface also demonstrated the strong professionalism of Shenzhen Gongkan's engineers. First, refer to the geological survey report to understand the starting position of rock socketing and the design depth of the pile being constructed. Second, during construction, first use a 2.4m diameter drilling tool to drill into the rock layer until some fresh rock samples can be collected. After determining that they meet the requirements, replace with a 1.0m diameter drilling tool to continue drilling. After reaching or exceeding the guided starting position of rock socketing, sample and inspect while drilling. When the continuously obtained rock samples are fresh moderately weathered or slightly weathered granite, it can be taken as the starting position of rock socketing. Then, the "two-stage" hole-forming method is used for rock socketing, and the final rock-socketed depth meets the design requirements. This increases the rock-socketed depth, construction time, and construction difficulty, but ensures the construction quality of the foundation piles.
5. How to ensure efficient and stable operation of each equipment and each work face
Facing such a large project volume and numerous equipment working simultaneously, how to ensure the compactness of construction time at each work face and improve equipment utilization requires, at the beginning of the project, reasonable arrangement of equipment according to pile diameter, pile depth, and pile position requirements, layout of the site, mud pits, and pipelines, as well as handling the problem of muck removal in the city. Only by formulating a detailed plan in advance and implementing it, with flexible on-site arrangements when necessary, can the continuity of operations be maintained.
The above are also problems that many units encounter when receiving engineering projects, including equipment arrangement, efficiency estimation, schedule planning, etc. Through advance layout and reasonable planning, they can be handled with ease and confidence during project implementation. Bauer also has a dedicated engineering department, which, with years of engineering experience accumulated worldwide, provides rational suggestions and engineering consulting to Bauer customers. The German Bauer Group is a world-renowned manufacturer of foundation engineering and drilling equipment, and one of the world's most famous foundation engineering contractors. Headquartered in Schrobenhausen, Bavaria, Germany, it has a history of more than 200 years. The German Bauer Group's business is divided into three major segments: special foundation engineering construction, equipment manufacturing, and resource development. Its subsidiary, Bauer Maschinen GmbH, is currently the world's largest manufacturer of foundation engineering equipment. The close integration of foundation engineering construction and equipment manufacturing is the fundamental reason why the German Bauer Group has always maintained a leading position in the industry worldwide.
"Innovation, never stopping" is the corporate spirit inherited by German Bauer for 225 years, and it is also the fundamental reason why it has always maintained a leading position in foundation construction technology. For more than 20 years since entering the Chinese market, German Bauer has continuously launched new products with leading technology and excellent quality in the Chinese market, providing Chinese users with foundation construction equipment synchronized with Germany, and introducing the world's most advanced foundation construction methods to China, creating value for users and becoming a sincere partner of users in China's foundation construction industry.