Quality control method of hydraulic dynamic compaction reinforcing loess subgrade(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2020年5期
- Page:
- 15-26
- Research Field:
- 道路工程
- Publishing date:
Info
- Title:
- Quality control method of hydraulic dynamic compaction reinforcing loess subgrade
- Author(s):
- HU Jiangyang; XU Tianyu; YAN Ruipeng; HAN Dandan; ZHOU Zhijun
- 1. CCCC First Highway Consultants Co., Ltd., Xian 710075, Shaanxi, China; 2. School of Highway, ChanganUniversity, Xian 710064, Shaanxi, China; 3. Henan Wanli Transportation Science & Technology GroupCo. Ltd, Xuchang 461000, Henan, China; 4. Xian Changda Highway Engineering TestingCenter, Xian 710064, Shaanxi, China
- Keywords:
- road engineering; hydraulic compactor; layered compactness; effective reinforcement depth; peak acceleration
- PACS:
- -
- DOI:
- -
- Abstract:
- To provide a realtime monitoring method of the degree of compaction at different depths during the construction of the loess subgrade, the hydraulic force coefficient was introduced, and the hydraulic dynamic compaction model was established, rely on the capacity expansion project of Huangling to Yanan Expressway, and the indoor fullscale model test of the hydraulic compactor reinforcing the loess subgrade was carried out. Considering the impact of the dropping distance and the dropping numbers of the hydraulic rammer on the degree of compaction of the subgrade, the peak acceleration of rammer and the layered settlement of the subgrade were obtained, by arranging acceleration sensors in the center of the top surface of the rammer and excavating the subgrade layer by layer after the reinforcement. The correlation between the settlement of surface soil and the peak acceleration of hydraulic rammer under different working conditions were analyzed. The subgrade depth which settlement was 5% of the soil surface settlement was used as the research object, the effective reinforcement depth of hydraulic compactor in different working conditions were analyzed through linear interpolation method and regression analysis method. And the relationship between the degree of compaction of subgrade in layers and the peak acceleration of rammer was determined. The results show that the peak acceleration of rammer and the settlement of surface soil increase with the increase of dropping numbers and dropping distance, and the increase trend slows down obviously after 6 and 7 dropping numbers, which qualitatively indicates that the peak acceleration of rammer can reflect the compaction quality of subgrade in real time. The effective reinforcement depth of hydraulic compactor is more affected by the dropping distance than dropping numbers of rammer. When dropping numbers reaches 12, the effective reinforcement depth corresponding to the dropping distance of 2.2, 1.6 and 0.7 m is 1.49, 1.18 and 1.10 m, respectively. Considering the range of effective reinforcement depth, there is a quadratic function relationship between the peak acceleration of rammer and the degree of compaction of subgrade in layers under different working conditions. The average degree of compaction of subgrade is obtained by weighted average of the layered degree of compaction. 4 tabs, 13 figs, 29 refs.
Last Update: 2020-10-12