1、 Equipment Overview
Electric compaction deviceIt is a testing equipment designed according to the "Highway Geotechnical Test Regulations" of the Ministry of Transport, used for making compacted specimens (such as bearing ratio test CBR, rebound modulus test, etc.). Its core function is to drive the heavy hammer to fall freely through the electric system, compact the soil sample in layers, determine the relationship between soil moisture content and dry density, and determine the optimal moisture content and maximum dry density. The equipment supports two compaction modes: light (2.5kg hammer, 300mm drop height) and heavy (4.5kg hammer, 450mm drop height), suitable for two specifications of test tubes: Φ 100mm and Φ 152mm.
2、 Preparation before operation
environment check
The laboratory temperature should be stable at 5-35 ℃, humidity ≤ 85%, and avoid direct sunlight or strong electromagnetic interference.
Ensure that the equipment is placed on a flat and stable workbench, with the anchor bolts firmly fixed to prevent vibration displacement.
Power supply and grounding
When using a three-phase four wire 380V power supply (some models are 220V), an independent leakage protection switch is required.
The grounding resistance should be ≤ 4 Ω to avoid the risk of electric shock.
Equipment inspection
Check whether the compaction hammer, guide rod, test tube, casing and other components are intact, without cracks or deformations.
Clean the inner wall of the test tube and apply a thin layer of mineral oil (such as Vaseline) to reduce friction.
Check if the control components such as the counter, display screen, and emergency stop button are functioning properly.
3、 Operation steps
Sample preparation
Mix the soil sample according to the regulations, sieve it (usually 4.75mm or 2.36mm sieve), mix well, seal and let it stand for 24 hours.
Load into the test cylinder in 3-5 layers, with quality reference for each layer:
The diameter of the 152mm test tube is approximately 1700g per layer for the three-layer method and 900-1100g per layer for the five layer method.
Test tube with a diameter of 100mm: The three-layer method has a weight of approximately 800-900g per layer, while the five layer method has a weight of approximately 400-500g per layer.
After each layer of sample installation, use a scraper to level the surface and place a tracking board (or hair pulling device).
Parameter Settings
Light/Heavy Mode Switching:
Adjust the position of the hammer button on the top of the guide rod (A → B for light weight, drop height 300mm; keep A for heavy weight, drop height 450mm).
Replace the hammer head counterweight core shaft (unscrew it to a light weight of 2.5kg and keep it as a heavy weight of 4.5kg).
Setting of compaction times:
Set the total number of hits through the control panel dial (e.g. 30 times/layer x 3 layers=90 times).
Some models support automatic cycle counting, which automatically stops when the set value is reached.
Selection of test tube specifications:
φ 152mm test tube: Enable the "mobile working mode" (mode light on), and the worktable will automatically move backwards during the compaction process to ensure the center of the hammer strike.
Test tube with a diameter of 100mm: Enable the "stop working mode" (mode light off), fix the workbench, and continuously hammer along the edge.
Start compaction
Press the 'Start' button, the device starts working, and the display screen shows the remaining number of hits in real-time.
During the compaction process, it is strictly prohibited to touch the test tube or guide rod to avoid danger.
If you need to stop halfway, press the 'pause' button; Press the "emergency stop" button and cut off the power when there is a malfunction.
Interlayer processing
After the first layer of compaction is completed, lift the tracking board and use a scraper to "roughen" the surface (increase interlayer adhesion).
Repeat steps 2-3 to complete the subsequent layer compaction.
Sample extraction and storage
After compaction is completed, use a demoulder to push out the sample, measure the height and diameter, and calculate the volume.
The sample needs to be wrapped in plastic wrap to prevent moisture evaporation, and subsequent tests (such as CBR test) should be completed within 24 hours.
4、 Maintenance and upkeep
Daily cleaning
After each experiment, clean the residual soil samples on the test cylinder, hammer head, and guide rod with a soft bristled brush.
Avoid using corrosive cleaning agents to prevent damage to optical components (such as display screens).
Lubrication and rust prevention
Apply No. 20 engine oil to transmission components such as chains, gears, and guide rails every week to reduce wear and tear.
When not in use for a long time, spray anti rust oil on the metal surface and cover it with a dust cover.
periodic calibration
Check the drop height of the compaction hammer every quarter (calibrated with a laser rangefinder or ruler) and the weight of the hammer (weighed with an electronic scale).
Contact professional institutions annually to calibrate equipment accuracy and ensure compliance with standards such as GB/T 50123-2019.
troubleshooting
Not starting: Check if the power supply, fuse, and emergency stop button have been reset.
Counting abnormality: Adjust the gap between the magnet on the chain and the Hall switch (usually 2-3mm).
Hammer offset: Check the coaxiality between the test cylinder and the workbench, adjust the positioning pin or replace the test cylinder.
5Electric compaction deviceSafety precautions
Operational Security
Wear goggles and gloves during the experiment to prevent soil samples from splashing and injuring people.
It is strictly prohibited to reach into the test cylinder area or adjust components during equipment operation.
Electrical safety
Avoid using in damp environments to prevent electrical leakage.
Replace the power cord immediately if it is damaged, and do not use tape to wrap and repair it.
Mechanical safety
Regularly check the fastening of anchor bolts and transmission components to prevent equipment overturning or component detachment.
Two people need to cooperate during transportation to avoid collision or falling.