The HZ combi-wall system consists of H-shaped steel sheet piles and Z-shaped steel sheet piles. It can provide extremely high cross-sectional performance in marine engineering, especially in projects that require ultra-long steel sheet piles (such as port terminals and piers). Let's take a look at what should be paid attention to when using HZ combi-wall.
Here is the content list:
Advantages of installing HZ combi-walls
What problems should be paid attention to when installing HZ combi-walls?
lWhat is the installation method of HZ combi-walls?
Low cost. Provides equivalent or better cross-sectional properties (modulus) at a lower material cost, which means that the unit weight per square meter is lower than that of Larsen sheet piles. This will help save material costs, thereby saving project costs.
Wider than Larsen sheet pile. Fewer numbers or chip stacks are required, which will speed up the installation process. This will help save project time, thereby saving machine and labor costs.
The thickness is uniform. Compared with sheet piles where the thinnest part of the interlocking part is only 6.5mm, the uniform thickness makes it more stable during installation and is not easy to damage during installation.
The HZ combi-walls system can be installed on land and water in a similar way. The key element of the latest installation is the template. If the template is incorrect, the installation quality may be poor.
First, place and fix the template to avoid any displacement during driving. Then, place multiple HZ combi-walls King piles in the template. Then, drive the king's pile into the ground, preferably using a vibrating hammer to start, and use the steps of the pilgrim to "push the order".
Depending on the soil conditions and the geometry of the final structure, it may be necessary to use an impact hammer for the second drive stage: after removing the drive template, drive until the final result is restored.
Usually, only after the completion of the driving of the HZ combi-walls piles, the middle sheet piles are tilted and stacked. However, under difficult rock and soil conditions, the entire driving operation may need to be carried out in two stages:
The first stage: drive the king pile as deep as possible into the ground or a predetermined intermediate depth. Then penetrate and drive the middle sheet pile to the same depth as the king pile.
The second stage: drive in the HZ combi-walls, then lower the infill board to the design depth or discard it. It is recommended to use partially crimped AZ plates in pairs: interlocking specific crimping can increase the stiffness of the top plate pile, while at the bottom, the AZ plate is still "flexible enough" to accommodate the driving tolerance of the HZ combi-walls.
The HZ combi-walls must be driven into the correct position, vertically or in accordance with the specified hitting surface. A template with two levels of guidance.
This is the recommended method, which uses a rigid form work with two guiding layers and sets the theoretical position of the pile foundation on the guiding layer. The vertical distance between the two floors should be at least 3m.
The template should be placed as close to the ground as possible. The template can be placed on the ground, but it should be firmly fixed to prevent any displacement. However, it is recommended to support the form work on piles. When traveling underwater, the form work is supported on auxiliary piles above the water level. Depending on the design, this type of template can usually accommodate 5 to 9 king piles. These primary piles are driven by free hanging vibrators or impact hammers,
Vibrators are the most commonly used equipment. Inside the form work, an appropriate HZ combi-walls system (if applicable) should be used to avoid damage to the coating on the sheet pile (for example, using guide rollers).
After driving all the HZ combi-walls of the template, remove the template and reposition it. The last driven pile will be used as a guide for the new position of the form work to ensure the correct alignment and distance between the HZ combi-walls.
In fact, it can also be used as a support pile, but from a practical point of view, it is better to distinguish between these two functions. Then, the same driving equipment or a second piling team can be used to install the intermediate sheet piles.