High Pressure Rotary Jet Grouting for Saturated Soil Remediation
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Solution Overview
Problem
Existing in-situ remediation systems face challenges with insufficient injection pressure, low injection efficiency, small diffusion radius of the agent, and difficulty in ensuring effective grouting in saturated layers, particularly in low-permeability formations and complex contaminated sites.
Innovation Solution
The in-situ injection of soil and groundwater—high pressure rotary jet grouting system employs a double-pipe process using compressed air and liquid fluids to spread the remediation agent, achieving high injection pressure (25–30 Mpa) and large diffusion radius, suitable for a wide range of soil layers, including low to medium permeability formations, with a pneumatic percussion rotary drilling method to enhance construction efficiency and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If conventional in-situ injection methods are used, then the remediation agent can be injected into the ground, but the injection pressure is insufficient and the diffusion radius is small
Solution Approach 1:
The injection system is segmented into multiple functional components: a dual-pump system (grouting pump for liquid agent, water pump for carrier fluid), a multi-nozzle injection device with separate liquid and gas nozzles, and a segmented drill pipe system. This segmentation allows independent optimization of each component to achieve high-pressure injection with large diffusion radius.
Solution Approach 2:
The invention employs hydraulic principles by using a high-pressure grouting pump to inject liquid remediation agent through a drill pipe, and pneumatic principles by using compressed air or nitrogen gas injected through separate nozzles. The combination of hydraulic pressure (liquid agent injection) and pneumatic pressure (gas injection) creates a dual-pressure system that achieves both high injection pressure and large diffusion radius simultaneously.
2Quantity of substance
If high pressure injection is used to increase diffusion radius, then the agent can spread wider, but the injection efficiency decreases and construction time increases
Solution Approach 1:
The injection process maintains continuous useful action by using a dual-pump system that operates simultaneously or in coordinated sequence, ensuring continuous injection of both liquid agent and gas carrier. The drill pipe is continuously lifted while injection continues, and the process can be repeated multiple times without interrupting the overall remediation workflow, maximizing productivity while maintaining large diffusion radius.
Solution Approach 2:
The system incorporates dynamic elements including adjustable injection pressure and flow rate controls, a drill pipe lifting mechanism that can be raised to different heights to control injection depth and diffusion pattern, and variable gas-to-liquid ratio control. These dynamic adjustments allow optimization of injection parameters for different soil conditions and contamination depths, maintaining high efficiency across varying operational requirements.
3Device complexity
If conventional single-tube injection is used, then the device complexity is low, but the injection pressure is insufficient for saturated layers
Solution Approach 1:
The injection system uses a nested structure where the liquid agent injection tube is positioned inside the outer drill pipe, and gas injection nozzles are arranged around the liquid injection tube. This nested configuration allows multiple injection functions (liquid agent delivery, gas carrier injection, drilling) to be integrated within a single drill string assembly, achieving high injection pressure capability without proportionally increasing overall device complexity.
Solution Approach 2:
The drill pipe assembly serves multiple functions: it acts as the injection conduit for the liquid remediation agent, provides structural support for the injection nozzles, enables drill bit rotation for soil penetration, and facilitates drill pipe lifting and repositioning. The unified multi-functional design avoids the need for separate devices for each function, maintaining reasonable complexity while achieving the required high injection pressure capability.
4Reliability
If repeated injection is performed to ensure contaminant removal, then the remediation effectiveness increases, but the construction time and costs increase
Solution Approach 1:
The system performs preliminary action by injecting the remediation agent to the full designed depth in a single operation, ensuring complete coverage of the contamination zone from the outset. The drill pipe is lifted to predetermined heights corresponding to different contamination depths, and injection is maintained throughout the entire lifting process, eliminating the need for multiple separate injection operations and reducing total construction time while ensuring thorough contaminant removal.
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 significantly improves remediation efficiency, expands the application range to complex sites, reduces construction time and costs, and ensures effective contaminant removal with minimal disturbance to the soil and groundwater environment, maintaining the original bearing capacity of the foundation.
Implementation Method 1
spraying the high pressure liquid flow (remediation agent solution/slurry)... the injection pressure of the high pressure grouting pump is 25 ̃30 Mpa
Implementation Method 2
the air compressor is always turned on during the percussion rotary drilling process, the compressed air is used as the power source... the air pressure of the air compressor is 0.7 ̃0.8 Mpa
Implementation Method 3
using gas (compressed air) and liquid (remediation agent solution/slurry) fluids to spread the soil while cutting the soil from bottom to top to achieve thorough mixing of the remediation agent with soil and groundwater
Data Source
AI summary
An in-situ injection of soil and groundwater—high pressure rotary jet grouting in-situ remediation system and method. The system has an agent dispensing station, high pressure grouting pump, air compressor, rotary jet grouting drilling machine, second double-pipe water flow joint, automatic lifting mechanism for grouting drill pipe of rotary jet grouting drilling machine, high pressure jet drill pipe, inner tube for high pressure jet triple drill pipe, outer tube for high pressure jet triple drill pipe, agent jet nozzle, an air jet nozzle, cemented carbide block and a drill bit. Parameters are arranged according to the triangle method to ensure that the remediation area is covered within the diffusion radius of the agent. After positioning the GPS measuring point, a guided-boring rig is positioned at the center of the injection point. The high pressure injection remediation uses a double-pipe: using gas and liquid fluids to spread the soil while cutting the soil from bottom to top to achieve thorough mixing of the remediation agent with soil and groundwater; quickly combining laboratory testing to obtain parameters for remediation agent residues, pH values, and contaminant concentrations to verify the in-situ remediation effect and monitor the residual agent.