Rapid Impact Compaction Construction Method - Rapid Impact Compactor Test

According to the current subgrade construction process, when filling the abutment back, culvert back and retaining wall back, the construction site is narrow, it is difficult for large machinery to reach or operate, the compaction work and construction efficiency of small tamping equipment are too low, which makes the compaction quality of these parts unable to be effectively guaranteed, and finally forms the common quality problem of "abutment back bump" and local large settlement deformation after construction, which seriously affects the overall quality of the subgrade; In addition, the fill slope of subgrade is easy to form "erosion" damage due to loose surface washed by rainwater.

Rapid Impact Compaction is used to lift the rammer to a certain height through a hydraulic cylinder and then release it quickly. The rammer is accelerated to fall under the action of gravity, and indirectly tamps the soil through elastic parts and tamping plates. The effect on the soil is a combination of static and dynamic forces. The main force is power, which belongs to dynamic compaction. Dynamic compaction is a compaction process between compaction and static compaction, It is a new technology developed on the basis of tamping technology. 

The equipment is installed on the boom of an ordinary loader, which is easy to move. The impact depth of the compactor is 4.5m, and the effective depth is 2m. It can be used for single point or continuous compaction of the working face. It is suitable for the construction parts with narrow working faces. At the same time, the post construction settlement of culvert abutment backfilling can be effectively reduced through the operation reinforcement of Rapid Impact Compactor.

Before compaction, the subgrade must be inspected according to the compaction standard and flatness required by the design. After passing the inspection, the Rapid Impact Compaction points shall be arranged.

Arrangement of tamping points of Rapid Impact Compaction

Set out tamping points on the subgrade that has been constructed and tested as qualified according to the compaction standard required by the design, mark them with lime and number them, and then measure the initial elevation of each point according to the number. The Rapid Impact Compaction shall be in place according to the survey and setting out position to align the rammer with the point.

The reinforcement treatment area of abutment back is 6m away from the culvert abutment, 6 rows in total. The first three rows of tamping points are arranged in a quincunx along the distance of 1m from the hammer center. The fourth row of tamping points is 1.2m (transverse) * 1m (longitudinal), and the fifth and sixth rows of tamping points are 1.5m (transverse) * 1m (longitudinal). The minimum distance between the edge of the hammer and the abutment back is 0.2m. The layout of tamping points is shown below.

Test method of Rapid Impact Compactor

Combined with the site construction, the test site is selected to fill at the back of the culvert abutment. HC36 Rapid Impact Compactor is selected. The weight of the rammer is 3.2 tons, the stroke is 1.2 meters, the maximum potential energy of the rammer is 36 kilojoules, and the diameter of the rammer plate is 1.0 meters. During the test, the third gear is used to accumulate three hammers each time, and the level is used to measure the relative elevation after three hammers of each rammer to obtain the corresponding cumulative settlement and relative settlement. The dynamic penetration test is used to detect the change of ground bearing capacity before and after compaction. Finally, the overall settlement of the final abutment filling surface is measured on the compacted surface.

The above is the introduction to the layout of tamping points and test methods of Rapid Impact Compactor. The use of Rapid Impact Compaction in dealing with abutment back construction is characterized by high speed, high efficiency and high energy, which is very suitable for highway construction requirements and can effectively avoid abutment defects such as abutment bump.