Grout-Free Expandable Standpipe With Swage-Seal Anchoring
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Solution Overview
Problem
Conventional grouted standpipes require 24 hours for grout to set, slowing down tunnel excavation progress and increasing costs due to the need for extensive curing times and potential failure during high-pressure water conditions.
Innovation Solution
The use of an expandable standpipe with a swage seal, anchored and sealed using an inflatable packer, eliminates the need for grout by expanding radially outwardly to secure into the pilot hole, allowing for rapid anchoring and sealing within 30 minutes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grout is used to seal and anchor standpipes into the ground formation, then reliable sealing and anchoring is achieved, but the process takes 24 hours for grout to set, significantly reducing productivity
Solution Approach 1:
The patent replaces the chemical grouting process with a mechanical expansion system. An inflatable packer is inserted into the standpipe and inflated to expand a swage seal radially outwardly, mechanically forcing the standpipe against the pilot hole wall to achieve sealing and anchoring without requiring grout to set.
Solution Approach 2:
The patent uses pneumatic pressure from an inflatable packer to achieve the sealing and anchoring function. The packer is inflated with gas or liquid under pressure, causing the swage seal to expand radially and create a mechanical bond with the pilot hole, eliminating the need for time-consuming grout curing.
2Reliability
If grout is used to seal standpipes, then sealing is achieved, but the standpipes cannot be removed or reused since the grout sets permanently
Solution Approach 1:
The patent creates a dynamic sealing system where the swage seal can be expanded and deflated. The inflatable packer allows the standpipe to be inflated for sealing during operation, then deflated for removal or relocation, providing adaptability and reusability unlike permanent grout sealing.
Solution Approach 2:
The standpipe with the swage seal system can be deflated and removed from the pilot hole after serving its purpose, allowing the hole to be reused or the standpipe to be relocated. This contrasts with grout sealing where the standpipe remains permanently embedded.
3Device complexity
If conventional standpipes are used without expansion capability, then the structure is simple, but they cannot achieve rapid anchoring and sealing in high-pressure ground water conditions
Solution Approach 1:
The patent applies local quality by having only the portion of the standpipe that contacts the pilot hole wall be expandable. The swage seal is located at the critical sealing interface, while the rest of the standpipe remains simple and rigid, providing expansion capability only where needed for sealing in high-pressure conditions.
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 method enables faster tunnel advancement by up to 24 hours per ring of standpipes, reducing overall excavation costs and ensuring quicker grouting of the ground formation.
Implementation Method 1
the swage seal being expandable radially outwardly to anchor and seal the standpipe into the pilot hole
Implementation Method 2
an inflatable packer locatable within the standpipe for expanding the swage seal
Data Source
AI summary
A grout free expandable standpipe (10) and methods for its use for anchoring into ground formation (22) and injecting grout into the ground formation (22), without the need for first grouting the standpipe (10) into the ground formation (22). The expandable standpipe (10) has a swage seal (43) that can be expanded with a swage tool, such as, for example, a unitary construction inflatable swage packer (60), or similar, for anchoring and sealing the standpipe (10) into a pilot hole (16), without the need for grout. A grouting hole (96) can then be drilled through the bore of the expandable standpipe (10) and into the ground formation. Then grout can be injected into the ground formation (22) via the grout hole (96) without having to wait up to around 24 hours for grout to cure and harden to anchor and seal the expandable standpipe (10) into the pilot hole (16).