Backflow Control in Ground Anchor Grouting
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Solution Overview
Problem
The installation of ground anchors in high water pressure environments faces challenges with backflow, which can lead to erosion and requires costly solutions like de-watering or the use of preventers that need to remain during grout curing, limiting project efficiency and increasing costs.
Innovation Solution
A system that uses a pinch valve device and a flexible annular member to control backflow during grouting, allowing the preventer to be removed before the grout hardens, eliminating the need for waiting for curing and reducing cleaning and equipment costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional preventers are used to control backflow during grouting, then backflow control is achieved, but the preventer must remain in place during grout curing which increases project time and prevents equipment reuse
Solution Approach 1:
The preventer is divided into two functional parts: a reusable main body that remains outside the ground anchor, and a disposable seal assembly that is inserted into the ground anchor, performs its function, and is then removed. This segmentation allows the main preventer body to be reused while the seal assembly is discarded after a single use, eliminating the time loss associated with keeping preventers in place during curing.
Solution Approach 2:
The sealing function is extracted from the main preventer body and placed into a separate disposable seal assembly. This allows the main preventer to be removed and reused while the seal assembly remains in the ground anchor temporarily to perform its sealing function, then is removed before curing completes. The sealing action is taken out from the permanent structure and made temporary and disposable.
2Reliability
If preventers are left in place during grout curing to ensure backflow control, then reliability is maintained, but equipment cannot be reused and additional cleaning costs are incurred
Solution Approach 1:
The seal assembly is designed as a cheap, disposable component that is inserted into the ground anchor, performs its sealing function during grouting, and is then removed and discarded. The main preventer body remains as a reusable expensive component. This approach allows equipment reuse while maintaining reliability during the critical grouting operation.
Solution Approach 2:
The seal assembly is discarded after a single use, while the main preventer body is recovered and reused for subsequent operations. The temporary seal performs its function and is then removed and discarded, allowing the main equipment to be recovered and put back into service immediately, thus improving productivity and equipment utilization.
3Reliability
If de-watering methods are used to prevent backflow in high water pressure environments, then backflow control is achieved, but project costs increase significantly
Solution Approach 1:
The disposable seal assembly provides an inexpensive alternative to costly de-watering methods. The seal is a simple, low-cost component that can be inserted and removed easily, providing effective backflow control during grouting without the need for expensive de-watering equipment or processes. The low cost of the disposable seal makes this approach economically superior to de-watering.
4Reliability
If blank flanges are used to seal the preventer during grout curing, then backflow control is maintained, but additional materials and costs are required
Solution Approach 1:
The sealing function is extracted from the permanent preventer structure and placed into a separate disposable seal assembly that is inserted into the ground anchor. This eliminates the need for blank flanges or other sealing materials to be attached to the preventer during curing, as the seal is already positioned inside the ground anchor where it is needed. The sealing action is taken out from the preventer and placed where it can work independently.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces project time and costs by allowing the preventer to be reused immediately and eliminating the need for blank flanges, while ensuring controlled backflow during grouting and curing.
Implementation Method 1
a flexible annular member disposed around the hollow bar, where the flexible annular device is movable when the valve device is in the open position, from a first position along the hollow bar above the valve device through an interior cavity of the valve device to a second position below the valve device
Data Source
AI summary
Backflow during installation of a ground anchor is controlled using a preventer, and the preventer is removed during curing of grout and backflow. A cylinder may be inserted at least partially into a structure, and the preventer placed or attached atop the cylinder. A hollow bar may be extended through the preventer and cylinder into one or more layers of materials beyond the cylinder. Grout may be delivered to the layer(s) through the hollow bar, which may cause a viscous backflow to flow into the cylinder and preventer. During application of the grout, the preventer may be used to control a rate of backflow. After application of the grout, the preventer may put into an open position, and a seal assembly forced down the hollow bar, through an interior cavity of the preventer, to a position below the preventer, after which the preventer may be removed while the grout and backflow cure.