Rapid compaction test - Rapid impact compaction test method

Director

1. 1.The principle of rapid impact compaction

2. 2.Rapid impact compaction test point layout

3. 3.Rapid compaction test

According to the current roadbed construction technology, when filling the abutment backs, culvert backs, and retaining wall backs, there are small construction sites, inaccessible or inconvenient operation of large-scale machinery, and low compaction power and construction efficiency of small compaction equipment. The quality of the compaction cannot be effectively guaranteed, and eventually the common quality problems of "jumping on the back of the platform" and local large settlement deformation after construction are formed, which seriously affects the overall quality of the roadbed. Rain erosion is more likely to form "scour" damage.

The principle of rapid impact compaction

The rapid impact compaction uses the hydraulic cylinder to lift the rammer to a certain height and then releases it quickly. The rammer is accelerated to fall under the action of gravity, and the soil is indirectly rammed through the elastic parts and the ramming plate. The effect on the soil is static and The composite action of power, the main force is power, belongs to dynamic compaction, dynamic compaction is a compaction process between compaction and static compaction, and is a new process developed on the basis of compaction process. . The equipment is installed on the boom of an ordinary loader, and it is easy to move. The impact depth of the compactor is 4.5m, and the effective depth is 2 meters. It can carry out single-point or continuous compaction on the working surface, and is suitable for construction sites with narrow working surfaces. At the same time, it can effectively reduce the settlement of the back of the culvert after backfilling by the rapid impact compaction.

Before the subgrade is rammed, it must be inspected according to the compaction standard and flatness required by the design. After the inspection is qualified, the layout of the rapid impact compactor point shall be carried out.

Rapid impact compaction test point layout

On the subgrade that has been constructed and passed the test according to the compaction standard required by the design, the tamping point is released, marked with white ash and numbered, and then the initial elevation of each point is measured according to the number. The rapid impact compactor is positioned according to the position of the measured stakeout, so that the tamper is aligned with the point.

The reinforcement treatment area for the back of the platform is 6m away from the culvert and platform, with a total of 6 rows. The first 3 rows of tamping points are arranged in a plum blossom shape along the hammer center distance of 1m, the 4th row of tamping points is 1.2m (horizontal)*1m (longitudinal), the 5th and 6th rows of tamping points are 1.5m (horizontal)*1m (vertical) , the minimum distance between the edge of the rammer and the back of the table is 0.2m, and the layout of the tamper point is as follows.

Rapid compaction test

Combined with on-site construction, the test site is selected to be backfilled on the culvert platform. The HC36 rapid impact compaction is selected. The weight of the tamper is 3.2 tons, the stroke is 1.2 meters, the maximum potential energy of tamping is 36 kJ, and the diameter of the tamping plate is 1.0 meters. In the test, 3 gears were used to accumulate 3 hammers for tamping operation each time, and the relative elevation after each tamper was measured with a level gauge after 3 hammers was used to obtain the corresponding cumulative settlement and relative settlement. force changes. Finally, the overall settlement of the final backfill surface was measured on the compacted surface.

The above is the introduction of the tamping point layout and test method of the rapid impact compaction machine. The use of the rapid impact compactor in the construction of the bridge abutment has the characteristics of high speed, high efficiency and high energy, which is very suitable for the requirements of highway construction and can effectively avoid the bridge abutment jumping. Vehicle and other bridge abutment defects.