Settlement characteristics of underground excavation metro tunnelling beneath existing building in waterrich loess strata(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2018年03期
- Page:
- 80-87
- Research Field:
- 桥梁与隧道工程
- Publishing date:
Info
- Title:
- Settlement characteristics of underground excavation metro tunnelling beneath existing building in waterrich loess strata
- Author(s):
- ZHANG Jian1; 2; MA Enlin1; XU Shuoshuo1; XIE Yuan1; ZHONG Yujian1
- (1. School of Highway, Changan University, Xian 710064, Shaanxi, China;2. Xian Metro Co., Ltd, Xian 710018, Shaanxi, China)
- Keywords:
- -
- PACS:
- -
- DOI:
- -
- Abstract:
- To investigate the settlement characteristics of the building and surface during the tunnelling beneath existing building in waterrich loess areas and to ensure the safety of construction, based on the underground excavation section of Changtong Line (Changle Park Station to Tonghumen Station) of Xian Metroline 3 Tunnel, a threedimensional finite element model is established by using MIDAS/GTS.The building settlement curve, the post construction settlement distribution curve and the surface settlement cloud image after construction under the condition of pregrouting or no pregrounting. At the same time, combined with the field measured data, the settlement of the building, along with the excavations and the distribution of the surface deformation after the construction, was compared and analyzed. The results show that the settlement of the building is mainly affected by the excavation of the left tunnel under the two conditions, and the settlement rate reaches the maximum after the excavation of the lower section in left line. Moreover, the settlement reaches the maximum after the excavation of all the soil beneath the building. After the construction, the settlement of the building is symmetrical at the center of the left line. The maximum settlement of the building occurs at the foundation, which is 119.5 mm, and the differential settlement value is 120.5 mm. The maximum and differential settlement decreases by 74.7% and 75.6%, respectively, under the condition of pregrouting, respectively. The surface subsidence area is 2.5 to 3 times of the construction area, and the overall distribution is oblique W type, with a left groove that is slightly deeper. When the grouting is not reinforced, the settlement groove is deeper, reaching 112.3 mm, and the maximum value after grouting is 15.1 mm. Compared with the simulation, the field monitoring value is slightly larger. The reason for the deviation maybe that the actual geological conditions are more complex, and the settlements are affected by the various loads on the surface and the construction blasting. The cumulative settlement of the support project is 16 mm, which meets the control requirements and validates the results of the numerical calculation. Moreover, the results can provide a reference for the design and construction of subway under buildings in loess areas. 3 tabs, 15 figs, 19 refs.
Last Update: 2018-06-13