Evaluating Construction Risks of Modified Shield Machine Applicable to Soft Soils Based on Fuzzy Comprehensive Evaluation Method

Abstract

Metro tunnel sections in China can generally be divided into two types, those in granite formations (D = 6.0 m) and those in soft soils (D = 6.2 m), to which the same shield tunnel machine cannot be applied. The consequent low rate of machine utilization needs to be addressed. One solution is to modify shield machines which tend to tunnel granite strata with varying degrees of weathering (D = 6.0 m) into those applicable in soft soils (D = 6.2 m). Shield tunneling is a complex operation accompanied by potential risks, and accordingly it is demanded in risk evaluation and management. Hence, according to the construction features of modified shield machines in soft soil areas, this paper identifies relevant risks before establishing a specific model of risk evaluation by virtue of a fuzzy comprehensive evaluation method. This model weighs risk factors by triangular fuzzy numbers, and the membership function included is of L-R type that is frequently used in engineering. This risk evaluation model is applied to one section tunnel (Binhai New Town-Lianhua) of Metro Line 6 in Fuzhou City. Tunneling tests in the field uncover problems of the modified shield machine, including inappropriate tunneling parameters, segment dislocation, segment damage, and inadequate grouting. The result conforms to that produced by the risk evaluation model, which in turn proves the reliability of this model. Field data are also analyzed to address existing problems and to determine the appropriate tunneling parameters. The validity of these tunneling parameters is verified when surface settlement is measured.

Quality Evaluation of College Employment Based on Fuzzy Comprehensive Evaluation and Immersive Virtual Realization Technology

“…e collection of evaluation indicators is carried out with the help of the perceptual vocabulary classification method, which is to use the hierarchical inference method to establish a tree-like analysis chart and gradually refine the details [12]. e implementation procedure is shown in Figure 3.…”

Investigation into the Electrohydraulic Synchronous Motion Control of a Thrust System for a Tunnel Boring Machine

“…A conventional PID strategy has been widely used in industrial projects with its adaptability characteristics [26]. As to thrust control system, internal parameters such as fluid volume, which vary with the elastic modulus of oil and external load disturbances, which vary by advancing periods, bring a disadvantageous influence into the system [27].…”

AHP‐FSE‐Based Risk Assessment and Mitigation for Slurry Balancing Shield Tunnel Construction

“…Research on risk control of slurry shield construction is still in its infancy. Most of existing researches are oriented to key technologies, such as ground settlement control [ 6 – 9 ], numerical simulation of tunnel excavation process [ 10 , 11 ], influence of shield tunneling that go through existing structures [ 12 – 16 ], and with less research on safety risk control [ 17 – 20 ]. In fact, it is of great significance to improve the safety of slurry shield construction to clarify the composition of safety risks and carry out safety management from the beginning of whole life cycle of project.…”