| With the rapid development of China’s economy, more and more urban population is increasing, so the road congestion has become serious increasingly. Due to the limited space of the upper part, the reasonable utilization of underground space is being concerned gradually by people. In order to reduce the settlement of the road surface and ensure the normal operation of the vehicle when the underground space is under construction, the pipe roof-box culvert of jacking method has been applied effectively with its unique advantages in underground engineering. Compared to other methods, the pipe roof-box culvert of jacking method is relatively safe, and has little effect on the surrounding soil and buildings or other facilities, at the same time, it can control the the settlement of the road surface effectively and ensure the construction engineering normally. In a word, for underground space engineering, how to control the settlement of the road surface effectively under the condition of ensuring the safe operation of vehicles is an important part of planning, design and construction.Therefore, in this paper, according to the 12# box culvert engineering in the west of Zhengzhou Jinshui Road(Songshan road-Jinshui Road), and the influence of the settlement of highway on the box Culvert Jacking Construction as the main research object, around the following aspects to research:(1) When the box culvert jacking is under construction, monitoring data should be recorded accuratly and timely, and the change of cause and rule for surface settlement is concluded. At the same time, the rationality of construction projects is researched, and the technical measures of reducing surface subsidence is discussed.(2) The project adopts the advance support technology of large pipe roof, the box culvert jacking process the settlement of road surface is inhibited effectively when the box culvert jacking is under construction, so the mechanical action mechanism of pipe roof should be analysised correctly, and the importance of pipe roof should be mastered in the engineering. Steel pipe has a reinforcing effect for soil, and it is similar to "reinforced earth", at the same time, the mechanism of pipe roof in the over excavation and under dig for soil is considerred, it is concluded that unloading ratio,overload ratio calculation method and the force deflection curve of pipe roof. When soil is over excavation, pipe roof is settlement, and part of the upper soil load by pipe roof transfers to the active zone on both sides, so it has the unloading function; when soil is under excavation, pipe roof is uplift phenomenon, and part of the upper soil load by pipe roof is delivered to the passive region, increasing the earth pressure on the excavation face, so it inhibits the uplift of the road surface.(3) In this paper, under certain assumptions, the ABAQUS finite element software is used to simulate the whole process of box culvert jacking, analyzing the changes of the road surface settlement, and the law of the change of the road settlement is summed up. |
