Application of rapid impact compactor in Qinghai Expressway in China

The dxtj-05 section of Qinghai Delingha Xiangride expressway is 23 kilometers long, including 1 bridge, 6 bridge channels, 14 culvert channels, 21 backfill on the back of bridge and culvert platforms, and 1 rapid impact compactor used in this section.

In order to better control the effect of dynamic compaction, the compaction test of rapid impact compactor is carried out at first. The test point is No. 7 abutment of sulingguole bridge with the central stake number of k87+910 in the bid section. The backfill of the abutment is gravel soil, some of which are clay, with low water content and high sand content. Hc36 type rapid impact compactor is used at the test site. The completed backfill at the back of No. 7 abutment is arranged according to a certain spacing density, so as to improve the compactness of the backfill at the back of the platform and minimize the problem of bridge head jumping during the operation of the expressway.

The foundation at the back of the abutment shall be leveled and rolled, and the working site shall be leveled. Identify the compaction range with a white gray line, and then measure the initial elevation of each point according to the number. The rapid impact compactor shall be in place according to the marked position, so that the rammer of the rapid impact compactor can be aligned. The compactor is divided into strong, medium and weak compactors according to its compaction capacity. The compactor is adjusted to strong compaction. The strong compaction of each compaction point is 6-9 times, and three times of compaction is a group. The relative settlement difference between the last group and the previous group is less than 10mm. According to the field test results, it can be seen that strong 6-9 blow operation can enhance the quality of bridge and culvert abutment back and greatly improve the operation efficiency.

Due to the large influence depth of the compaction process, after the reinforcement of the rapid impact compactor, the overall settlement of the back of the bridge and culvert platform is 32mm, which eliminates the problems of post construction settlement and insufficient rolling effect in the construction process.

The rapid impact compactor has good mobility, controllability and efficiency, and can uniformly improve the deep compaction of the filler. The phenomenon of vehicle jumping at the bridgehead after the opening of expressway bridges and culverts has been significantly improved.