I. Introduction: Choosing the Right Tool for Precision Grouting

The choice of grouting pipe significantly determines the efficiency, cost, and long-term success of any ground stabilization or void filling project. While the basic Conventional Grouting Pipe (or Injection Pipe) serves simple injection needs, the specialized Perforated Grouting Pipe (often referred to as a Sleeve Pipe or Manchette Tube) offers a level of precision and control unmatched by standard methods.

Understanding the structural differences and functional advantages of these two main types is crucial for engineers when designing a targeted and effective grouting program.

II. Conventional Grouting Pipes (Standard Injection Pipe)

A conventional grouting pipe is the simplest form of injection delivery system.

A. Structure and Function

• Structure: Typically a simple Steel Grouting Pipe or PVC pipe with an open end or a series of small, uniform perforations along its length (often called a 'flower pipe' or '花管' when perforated).

• Injection Method:

1. Single-Stage Injection: Grout is pumped down the pipe, exiting the bottom or the perforations simultaneously along the pipe's entire length.

2. Lack of Control: Once the pipe is set and grouting begins, it is difficult or impossible to control the exact depth or pressure at which the grout exits the pipe.

• Keywords: Conventional Grouting Pipe, Standard Injection Pipe, Steel Grouting Pipe.

B. Suitable Applications

Best suited for simple applications where the entire treatment zone requires the same uniform amount of grout, such as:

• Shallow soil stabilization.

• Single-pass void filling.

• Low-pressure pre-injection (as briefly used in some tunneling projects, detailed in 【Tunneling-Application】 Tunnel Grouting Pipes and Pre-Injection Pipes).

III. Perforated Grouting Pipes (Sleeve Pipes/Manchette Tubes)

The Perforated Grouting Pipe is designed for sophisticated, multi-stage, and repeatable grouting operations.

A. Structure and Function

• Structure: A rigid pipe (usually steel or high-density plastic) featuring a series of closely spaced, small holes (perforations) along its length. Each set of perforations is covered by a flexible rubber sleeve (the manchette).

• Injection Method: Multi-Stage Grouting:

1. A specialized double-packer assembly is lowered into the pipe to the desired depth.

2. The packers are inflated, isolating the segment of the pipe between two sleeves.

3. Grout is injected under pressure, forcing the grout out of the perforations, past the rubber sleeve, and into the ground.

4. The sleeves act as one-way valves, preventing grout from flowing back into the pipe.

• Keywords: Perforated Grouting Pipe, Sleeve Pipe, Manchette Tube, Controlled Injection Pipe.

B. Key Advantages of Perforated Grouting Pipes

IV. Applications Requiring Precision and Control

The cost and complexity of the Perforated Grouting Pipe are justified when precision is paramount:

1. Deep Foundation Reinforcement: Targeting specific weak soil layers or zones identified through testing, ensuring effective foundation grouting as outlined in 【Foundation-Application】 Foundation Grouting Pipes: Applications in Foundation Reinforcement.

2. Barrier Construction: Creating low-permeability cut-off walls for environmental projects.

3. Compaction Grouting: Allowing repeated injections to systematically densify specific soil strata.

V. Conclusion: Matching the Pipe to the Purpose

While the conventional grouting pipe remains useful for simple, bulk applications, the perforated grouting pipe (sleeve pipe) provides engineers with the essential control, selectivity, and repeatability required for complex ground improvement and defect remediation projects. Selecting the best pipe type means matching the pipe's technical capability to the geotechnical demands of the site.