One-lung ventilation (OLV) has been commonly provided by using a double-lumen tube (DLT). Previous reports have indicated the high incidence of inappropriate DLT positioning in conventional maneuvers.After obtaining approval from the medical ethics committee of First Affiliated Hospital of Anhui Medical University and written consent from patients, 88 adult patients belonging to American society of anesthesiologists (ASA) physical status grade I or II, and undergoing elective thoracic surgery requiring a left-side DLT for OLV were enrolled in this prospective, single-blind, randomized controlled study. Patients were randomly allocated to 1 of 2 groups: simple maneuver group or conventional maneuver group. The simple maneuver is a method that relies on partially inflating the bronchial balloon and recreating the effect of a carinal hook on the DLTs to give an idea of orientation and depth. After the induction of anesthesia the patients were intubated with a left-sided Robertshaw DLT using one of the 2 intubation techniques. After intubation of each DLT, an anesthesiologist used flexible bronchoscopy to evaluate the patient while the patient lay in a supine position. The number of optimal position and the time required to place DLT in correct position were recorded.Time for the intubation of DLT took 100 ± 16.2 seconds (mean ± SD) in simple maneuver group and 95.1 ± 20.8 seconds in conventional maneuver group. The difference was not statistically significant (P = 0.221). Time for fiberoptic bronchoscope (FOB) took 22 ± 4.8 seconds in simple maneuver group and was statistically faster than that in conventional maneuver group (43.6 ± 23.7 seconds, P < 0.001). Nearly 98% of the 44 intubations in simple maneuver group were considered as in optimal position while only 52% of the 44 intubations in conventional maneuver group were in optimal position, and the difference was statistically significant (P < 0.001).This simple maneuver is more rapid and more accurate to position left-sided DLTs, it may be substituted for FOB during positioning of a left-sided DLT in condition that FOB is unavailable or inapplicable.

In this paper, FLAC3D, the general software for geotechnical engineering project, is used to conduct two-dimensional numerical simulation for typical shallow tunnel excavation methods which include full-section method, the upper and lower step method, three-step method and CRD method etc.Effects of different excavation methods to the stability of tunnel surrounding rock are analyzed. The paper selected a subsistent tunnel as the research object. With construction simulation of different excavation methods, the paper makes comparative analysis of laws and characteristics of displacement of tunnel surrounding rock , stress distribution and size of plastic zones under different excavation methods. Study shows that: Ι.Followed by two step method, CRD engineering method and the full-section method successively, the three-step method is the best in the aspect of control of surrounding rock stress,; ΙΙ. Followed by full-section method, two- step method and the three step method successively, CRD engineering method is the best,in the aspect of size of plastic zones; Ш. Followed by three-step method, two-step method and the full-section method, CRD construction is the best in the aspect of control of surrounding rock displacement.

The main purpose of this paper is to analyze the stability and safety problems of braced excavation enclosure, surrounding strata and side slope during construction of Shangshuijing station in Shenzhen Metro Line 5. The paper presents stability discrimination of the braced excavation and side slope by discussing their force and deformation regularity using Flac3D, and puts forward some project proposals about its design and construction. The results show that: (1) The stability coefficient of braced excavation enclosure becomes smaller because of biasing impact of side slope, but this project can meet the stability requirements, (2) The biasing impact of side slope has little influence on deformation of surrounding strata starting on the other side of braced excavation without slope, and (3) To ensure construction safety under condition of side slope, the braced excavation should be excavated starting from the zone far from the side slope, steel pipe can be used as assistant reinforcement at the corner of side slope if necessary.