This is the construction site of Songwan 110KV power transmission and transformation project in Shaoxing City, Zhejiang Province. The whole project is divided into the following four lines: Honghu-Binhai to Haitan 110kV line project, Honghu-Sanjiang T-connecting Haitan substation 110kV line project , Honghu-Sanggang to Songwan 110kV line project and Sanggang-Mahai 110kV line expansion and reconstruction project. The new tower in front of me has been erected high. So what’s the difference between it and other iron towers? Of course there is, the answer lies in the foundation of the electric tower. The foundation of this electric tower adopts a new type of helical pile foundation with a cement cap.
Helical pile, also known as screw anchor, is a new type of foundation construction technology. Its advantages lie in fast construction speed, low construction difficulty, and good installation effect. The spiral anchor foundation can be used not only in power transmission and transformation projects, but also in the foundation construction of bridges, highways, buildings and other projects. The equipment used in the installation of the screw anchor is called the helical pile informatization installation system. This system consists of a driving head, a verticality monitor, a torque detector, and a monitoring system in the cabin. During the construction process, the torque and verticality data can be monitored in real time. , through this system, the operator can ensure that the verticality of the helical pile installation and the bearing capacity are up to standard, so that the pile body can be installed accurately.
At the construction site, we can see that this set of equipment can be assembled on the XCMG 305 excavator. The powerful power head can easily “screw” a nearly 10-meter-long helical pile into the ground. After the “large screw” is screwed into the soil, it can withstand a pressure of 70-80 tons and a pull-out force of 30-40 tons. It is connected with the cement cap or steel cap in the soil and becomes the whole of the foundation of the tower, jointly resisting the uplift force, downforce and horizontal force. The insertion method of the helical pile can be straight or inclined, and the inclined single-anchor foundation is more in line with the mechanical characteristics and more scientific.
So is this kind of tall tower foundation construction expensive? Of course not. At present, its cost is basically the same as that of traditional construction, but its efficiency has been greatly improved, and it is more green and environmentally friendly! Especially suitable for plain and hilly terrain construction. If you want to build a strong electric tower, laying a solid foundation is the key. The function of the helical pile foundation is to make the tower stand firmly. It is the first choice for future tower foundation construction.
The degree of adaptation between the helical pile and the pile foundation of the high-voltage electric tower is very high, which is mainly reflected in the following key aspects.
The first is the bearing capacity. The helical pile has a high bearing capacity. The steel helical pile can be selected according to the specific soil conditions and design requirements during design to ensure that its bearing capacity meets the requirements.
The second is installation efficiency. The installation of helical piles is relatively simple and quick, and does not require large mechanical equipment or concrete pouring process. During installation, the helical pile is fixed at the required depth by screwing into the ground, which can quickly complete the construction of the entire pile foundation.
Then there is soil adaptability, helical piles are suitable for various soil conditions, including soft soil, sandy soil, clay and so on. Since the helical pile enters the ground through rotation, its special shape can provide greater lateral friction and bearing capacity, thereby enhancing the stability of the pile foundation.
The last is environmental protection. Compared with traditional concrete pile foundations, the installation process of helical piles does not require a lot of cement and water resources, which reduces the impact on the environment. In addition, helical piles can be reused or dismantled, which has high sustainability.
In conclusion, the helical pile foundation is a high-efficiency, energy-saving, environmentally friendly, safe and reliable foundation construction technology with broad application prospects. With the continuous development and improvement of technology, helical pile foundation will gradually become one of the main construction methods of foundation engineering.