Inspection method of closed water test

1. Diagram of closed water test device

2. Closed water test

2.1. Check whether the plugs at both ends of the access pipeline of the inspection well are blocked.

2.2. Fill the inspection well with water and increase the pressure to 0.1MPa, drain the internal air, and keep the pressure constant for 5 minutes.

2.3. Observe whether there is water leakage on the outer surface of the inspection well, and make a record.

2.4. If there is no water spray, seepage or flow within the specified inspection time, it will meet the standard requirements.

Schematic diagram of loading test:

3. Bearing capacity test

3.1. The outer diameter of the steel bearing plate (rigid pad) for the axial bearing capacity test should not be less than the outer diameter of the well circle, the inner diameter should not be larger than the inner diameter of the well circle, and the steel plate thickness of the steel bearing plate should not be less than 40mm.

3.2. The outer diameter of the steel bearing plate (rigid cushion block) for the bearing capacity test of the top and bottom plates is 356mm, and the thickness of the steel plate of the bearing plate shall not be less than 40mm.

3.3. The contact surface between the steel bearing plate (rigid cushion) and the inspection well components should be provided with suitable soft materials.

3.4. For inspection well products that adopt steam curing, the inspection age should not be less than 14 days; for inspection wells that adopt natural maintenance, the inspection age should not be less than 28 days.

3.5. Check the condition of the test equipment, and use it only when there is no fault in the equipment.

3.6. Place the test piece on the test device, and then place the pressure-bearing plate at the required position of the sample to be inspected. The loading point should be set at the center of the pressure-bearing plate.

3.7. Start the oil pump and apply the load to the pressure plate at a loading speed of about 25KN/min.

3.8. Continuously load at a constant speed to 80% of the standard value of the bearing capacity load (Po or Pt), keep it for 1 min, observe whether there are cracks in the pressure parts of the inspection well, if there are cracks, use a reading microscope to measure and record the crack width; if not, If cracks appear or the crack width is less than the standard, continue to load 10%, keep for 1 min, observe whether there are cracks and measure and record the crack width; then load to the required bearing capacity load value (Po or Pt), and act on the bearing capacity load value Keep it for 3 minutes, observe whether there are cracks and measure and record the width of the cracks.

3.9. Test result: If the crack width is less than 0.20mm under the action of the bearing capacity load value (Po or Pt), the bearing capacity test is qualified. The formula for calculating the pressure value of the bearing capacity test:

Pressurization value = bearing capacity load value (Po or Pt)-self-weight of the pressurizing facility, in kilonewtons (KN).