The subgrade reinforced by hc36 Rapid Impact Compaction is also suitable for evaluating the relative settlement of subgrade. Larger compression rate and settlement not only represent the improvement of soil specific compaction (strength), but also mean the improvement of soil symmetry. Larger compression rate and settlement not only represent the improvement of soil specific compaction (strength), but also mean the improvement of soil symmetry. Improving soil symmetry is conducive to improving the resistance to vehicle dynamic load.

The repeated rolling of the roller can not improve the quality of the subgrade. The more hammering times of the Rapid Impact Compaction, the better the effect. Therefore, under the condition of ensuring a certain quality, when determining the construction and inspection requirements, there should be relevant factors such as enforceability, productivity, cost and so on.

Refer to the following procedures and methods to determine the construction requirements and test standards of hc36 Rapid Impact Compaction.

(1) Select the test section. Try to choose the road under normal construction in the near future, and do not take temporary improvement measures such as pressure supplement before the experiment.

(2) Determine several inspection points in the test section and mark them. Typical inspection points cannot be selected in the dump truck.

(3) The Rapid Impact Compaction is set as three-stage three hammer continuous compaction. (when the height is large, tamp continuously for 3 times). After tamping 3 hammers each time, check the settlement of tamping point until the cumulative settlement of about 30 hammers or 3 hammers is less than 15mm (high-speed rail: 10mm). The number of blows shall be reduced in case of lack of structures and other inspection points.

(4) The dynamic penetration detection points can be cut according to the number of 9 hammers, 12 hammers, 15 hammers or more in the third gear. After measuring the settlement, excavate (the excavation depth is as required, most of which are 0.6~1m), and conduct the dynamic touch test.

(5) Sort out the data test, and determine the corresponding number of blows and the corresponding settlement according to the provisions of subgrade bearing capacity or bearing capacity lifting value, as the basis for construction and test.

In the experiment, when the Rapid Impact Compaction has a large number of hammers, the non rammed part adjacent to the ramming plate may protrude partially, which is caused by the surface or shallow part loosening under the impact and extrusion and the part not directly rammed. The lower soil is still reinforced, and it is inappropriate to explain it with lamination technology.

In the normal construction process, the number of click hammers can be appropriately adjusted according to the specific settlement. When the settlement of the blow count is required to exceed the control value, it should be solved differently.

(1) When the settlement exceeds 20% of the control value, moderately reduce the number of blows between the adjacent four points, and supplement the compaction or do not solve it.

(2) When the settlement exceeds 20% to 50% of the control value, supplementary compaction shall be carried out between adjacent 4 points.

(3) When the settlement exceeds 50% of the control value, it indicates that the lower soil mass is weak, and some excavation and refilling or other reinforcement measures are taken.

(4) Jtgf10-2006 requirements and design requirements are usually used to solve the adjacent abutments by using small compactors, and some use heavy rollers for rolling, which has poor effect, and the reinforcement settlement is significantly higher than the normal rolling parts. It is suggested to revise the construction standard (newly added, a total of 2 places). When compacting in layers, a large amplitude vertical vibration compactor with compaction strength greater than that of a heavy roller should be used.

(5) When solving the problem of tens of meters high fill, due to the great influence of the Rapid Impact Compaction, with the increase of the fill thickness, the settlement of the number of blows of the Rapid Impact Compaction may exceed the data of the test section.

(6) The filling quality of the excavated part of the old subgrade of the widened pavement varies greatly, and the number of blows can be adjusted appropriately according to the specific situation of the site.

When completing the subgrade acceptance, a simple evaluation of the relative settlement can be selected, and the subgrade that significantly exceeds the average settlement must be of poor quality.