RESUMO
In the construction of tunnels under existing stations, it is necessary to control their settlement. When there is a pile foundation in the existing station, the pile cutting has a significant impact on the settlement of the existing station. To determine the influence of existing piles on the settlement of subway stations, a reasonable pile-cutting time is proposed. Based on the Chengdu Metro Line 9 underpassing the existing Line 1 hatchery station, the settlement law of the tunnel underpassing the existing Line 1 station is analysed via a numerical simulation. Furthermore, the deformation and stress characteristics of the existing piles, pipe roofs, and tunnel linings and the supporting effect on the existing station are discussed. It is concluded that the cutting of existing piles causes a change in the tunnel bearing system, thus resulting in a certain deformation of the station. The influence of different pile cutting times on the settlement of the existing station is then analysed, and it is clarified that the tunnel support stiffness is significantly enhanced after the construction of the secondary lining. At this time, the settlement of the existing pile station is significantly reduced. Finally, through a field investigation, the effect of surface grouting, pipe shed, and multilayer lining on the settlement control of the existing station while the existing pile foundation exists is determined. This research can provide a reference for the settlement control and foundation underpinning of existing stations at ultra-small distances in underground excavation tunnels.
RESUMO
Objective: This paper aims to analyze the clinical effect and prognosis of neuroendoscopy-assisted surgery for chronic subdural hematoma (CSDH). Methods: The clinical data of CSDH patients who underwent surgery between March 2018 and June 2020 in the Department of Neurosurgery of the First Affiliated Hospital of Xiamen University were retrospectively collected and analyzed. Eighty patients with CSDH who met the inclusive criteria were selected. A control group (32 cases treated with burr hole drainage) and an observation group (48 cases treated with neuroendoscopy-assisted surgery) were set according to different operation methods. The hematoma clearance rate, surgery-related indicators, related complications, hematoma recurrence rate and related prognostic indicators of the two groups were compared and analyzed. Result: The postoperative hematoma clearance rate of the observation group was 92.59%, which was higher than that of the control group (77.78%) (P<0.05). The operation time of the observation group was longer than that of the control group (P<0.05). The postoperative hospitalization time of the observation group was shorter than that of the control group (P<0.05). The postoperative complication rate of the observation group was lower than that of the control group (P<0.05). The recurrence rate of hematoma in the observation group in the six-month postoperative follow-up was 1.85%, which was lower than that in the control group (P<0.05). The limb motor function and daily living ability score of the observation group were higher than those of the control group, and the Markwalder grading score was lower than that of the control group (P<0.05). Conclusion: Neuroendoscopy-assisted treatment which is safe and effective is superior to traditional burr-hole drainage surgery. It can reduce the recurrence rate; thus, it is worth advocating and applying.
