07/07/2025
📌 1. Nguyên lý hoạt động của hệ thống CMS
CMS là phương pháp cải tiến của phương pháp trộn sâu thông thường (DMM – Deep Mixing Method), có đặc điểm:
Sử dụng 2 vòi phun vữa (Slurry injection nozzles) để tăng cường hiệu quả trộn.
Kết hợp các loại cánh trộn khác nhau (Mixing blade, Stationary blade, Drilling blade).
Có hệ thống xoay ngược chiều giữa các trục khoan (counter-rotating shafts) để tăng khả năng phá vỡ đất dính.
📌 Detailed Summary of the CMS (Cement Mixing System) Technology
📘 1. Working Principle
The CMS is an enhanced Deep Mixing Method (DMM) that utilizes:
- Two medium-pressure slurry injection nozzles for better cement dispersion.
- Multiple blade types (Mixing blade, Stationary blade, Drilling blade) for efficient mixing.
- Counter-rotating shafts that generate high shear forces, especially effective in cohesive soils.
🛠️ 2. Key Equipment Components
According to the diagrams:
Component Function
Stationary Blade (A) Provides lateral shear and resistance to aid in breaking up soil clumps.
Mixing Blade (B) Rotates to mix soil and slurry thoroughly.
Drilling Blade (C) Cuts into the ground during downward pe*******on.
Slurry Nozzles (D) Injects cement slurry into the soil under medium pressure (5–20 MPa).
⚙️ 3. Advantages of Dual Nozzles
When mixing in viscous soils, a single nozzle often leads to bunching up of soil and slurry, causing ineffective agitation.
CMS solves this by using two offset nozzles, which:
- Increase slurry distribution range
- Improve mixing uniformity
- Reduce unmixed soil pockets
🏗️ 4. CMS Equipment Setup
As shown in the system diagram:
Component Role
GI Machine Main mixing/drilling rig
Cement Silo Cement storage
Mixing Plant Blends water and cement to produce slurry
High-Pressure Pump Delivers slurry to nozzles under pressure
Generator Provides power to the system
Slime Pit Collects waste slurry and soil cuttings
📏 5. CMS Technical Specifications
Parameter Value
Soil Type Cohesive soil: N < 11; Sandy soil: N < 15
Column Diameter φ = 500 mm – 1600 mm
Improvement Depth Avg: 15 m (Max achieved: 23 m)
Injection Pressure 5 MPa – 20 MPa
🟢 Ideal for deep soft soil treatment in ports, highways, and industrial zones.
🔄 6. Twin Shaft + Counter-Rotation
Dual shafts rotate in opposite directions for enhanced mixing efficiency.
Creates horizontal and vertical shear forces → stronger, more uniform soil-cement columns.
Reduces risk of weak zones due to poor mixing.
✅ Key Advantages of CMS Compared to Traditional DMM
Feature CMS Technology
Mixing Efficiency High (dual nozzles + counter-rotation)
Soil Type Compatibility Excellent in clay, silt, soft marine deposits
Column Diameter Up to 1.6 m
Mixing Uniformity Consistent and reliable
Application Areas Road embankments, ports, railways, industrial platforms.
GEOS Engineering Geotechnical World Geotechnical & Highway Engineering Geotechnical Engineering Association