Pressure Relief Well Structure for Weakly Permeable Soft Strata
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Solution Overview
Problem
Traditional drainage pressure relief systems are ineffective in weakly permeable soft strata due to poor permeability, difficulty in construction, and potential well settling, especially in coastal areas with deep soft strata, leading to increased costs and system failures.
Innovation Solution
A drainage pressure relief system with an artificial hydrophobic layer comprising a wicker fence, biaxially stretched plastic geogrid, medium coarse sand, and crushed stone layers, combined with a steel-plastic composite pipe and spiral stirrups, anchored longitudinal bars, and a self-contained sump, to enhance permeability and prevent well settling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional pressure relief wells are arranged in weakly permeable soft stratum, then drainage function is provided, but precipitation funnel is too small and blocking is easy to occur
Solution Approach 1:
The patent applies porous materials by constructing an artificial hydrophobic layer with specific permeability characteristics around the pressure relief well. This layer includes multiple strata (gravel layer, sand layer, geotextile layer) with progressively reducing pore sizes, creating an optimized porous structure that enhances water infiltration while preventing clogging. The porous structure allows water to penetrate efficiently into the well while filtering out fine particles that would cause blocking.
Solution Approach 2:
The patent employs composite materials by combining different materials with complementary properties in the artificial hydrophobic layer. The composite structure includes gravel (for initial filtration and structural stability), sand (for intermediate filtration), geotextile (for fine particle barrier and structural integrity), and compacted soil (for anchoring and additional filtration). This composite approach creates a multi-functional barrier that simultaneously improves precipitation efficiency and prevents blocking.
2Reliability
If pressure relief wells are drilled deep to reach hard earth layer or rock layer, then well settling is prevented, but construction cost is greatly increased
Solution Approach 1:
The patent applies the anti-weight principle by using the buoyant force of water in the artificial hydrophobic layer to counterbalance the weight of the pressure relief well structure. The water-saturated porous layer creates an upward buoyant force that offsets the downward gravitational force on the well, preventing settling without requiring deep anchoring into hard strata. This reduces construction depth and associated costs while maintaining anti-settling reliability.
Solution Approach 2:
The patent introduces an intermediary element - the artificial hydrophobic layer - between the pressure relief well and the soft stratum. This intermediary layer serves multiple functions: it provides a stable bearing surface for the well, distributes loads evenly, prevents direct contact between the well and soft, settling-prone soil, and anchors the well through its compacted soil layer. This mediator eliminates the need to drill through deep soft strata to reach hard layers.
3Ease of manufacture
If construction is carried out in soft earth layer during rainy season, then pressure relief well can be installed, but construction difficulty increases significantly
Solution Approach 1:
The patent applies preliminary action by constructing the artificial hydrophobic layer and installing the pressure relief well in a predetermined sequence before final backfilling and site restoration. The method involves preparing the well site, installing the well structure, constructing the hydrophobic layer around it, and then backfilling - all planned in advance to avoid rainy season complications. This preliminary planning and staged construction reduce on-site complexity during adverse weather.
Solution Approach 2:
The patent employs self-service principles by designing the artificial hydrophobic layer to self-anchor and self-stabilize during construction. The layered structure with progressively compacted materials creates inherent stability as each layer is constructed, requiring minimal external support or complex temporary structures. The system essentially builds its own stability through the construction process itself, reducing the need for additional construction equipment and expertise during rainy 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
The system effectively enlarges the precipitation funnel, prevents well settling, and reduces construction difficulties and costs, ensuring reliable drainage pressure relief in weakly permeable soft strata, particularly in coastal environments.
Implementation Method 1
By laying an artificial hydrophobic layer, the permeability coefficient of a weakly permeable soft stratum is increased, the range of precipitation is enlarged
Data Source
AI summary
Disclosed in the present invention is a drainage pressure relief anti-floating system suitable for a weakly permeable soft stratum. The drainage pressure relief anti-floating system comprises a pressure relief well body and an artificial hydrophobic layer, wherein longitudinal bars are arranged in stand columns of a sand-free concrete well wall, and are anchored into concealed beams. The pressure relief well body is located in the artificial hydrophobic layer, a construction surface of the artificial hydrophobic layer is located on the weakly permeable soft stratum, a wicker fence layer is laid on the weakly permeable soft stratum, a biaxially stretched plastic geogrid is laid on the wicker fence layer, a medium coarse sand layer is laid on the biaxially stretched plastic geogrid, and a crushed stone layer is laid on the medium coarse sand layer.