| With the continuous growth of China’s economy,the urbanization process has been further accelerated,but traffic congestion has become an important factor restricting urban development.The competent departments of major cities are actively thinking about solving the problem of urban congestion.The subway has the advantages of large traffic volume,fast speed,punctuality,and no occupation of floor space.It is widely used.Shield method construction is the main form of tunnel construction in the subway section.When the shield has completed the initial and normal excavation stages,it will enter the final receiving stage.The risks of the shield steel sleeve receiving construction are manifold.It may cause hundreds of thousands to millions of economic losses,while causing heavy casualties and huge economic losses.Therefore,the research on the risk assessment and countermeasures of shield steel sleeve receiving construction is a very necessary research topic.In this paper,under the background of the research object of the shield steel sleeve receiving construction of Dong fang hong Square Station of Lanzhou Metro,through reading relevant literature,industry norms and standards,and on-site practical experience,we systematically analyzed various risk factors of steel sleeve receiving construction and identified Six first-level risk factors,including environmental risk,safety management risk,receiver construction risk,receiving tunneling construction risk,monitoring risk and social risk,and 25 second-level risks such as high water and soil pressure in the formation,overrun of the formation,and improper choice of shield tunneling speed factor.In this way,a risk identification coupling matrix based on the work breakdown structure and the risk breakdown structure is established,thereby establishing a risk list.Considering that in the past subjective weighting methods mostly rely on expert experience and strong subjectivity;while objective weighting methods overcome the influence of subjectivity,they have the characteristics of randomness of sample data.To this end,this paper uses the analytic hierarchy process to determine the subjective weights of the first-level risk factors and the second-level risk factors,the entropy weight method determines the objective weights,and then uses the combination of the analytic hierarchy process and the heirship method to determine the first-level and second-level risk evaluation indicators Comprehensive weight.Finally,the fuzzy comprehensive evaluation method was used to carry out a comprehensive evaluation,and it was concluded that the project’s risk level is four,which must be paid attention to and strengthened management.Based on the results of the risk assessment,on the basis of investigation and research,detailed countermeasures were formulated to achieve the purpose of avoiding,mitigating and transferring risks,and to minimize the risks of shield acceptance and construction.It has played a good role in the receiving process,and also provided valuable experience for the reception of steel sleeves in similar projects in other local cities. |
