Calculation And Regulation Method Of Space Conflict Risk For Arch Dam Pouring Under Wind Influence

Most of the concrete arch dams under construction and proposed in China are in narrow river sections with steep terrain and deep valleys,so space resources are extremely restricted.Limited by the construction technology,the arch dam pouring process requires a variety of machinery and labor to work together in the limited dam surface space,which can easily lead to cross-working space conflicts.At the same time,the narrow pipe effect in the construction area is significant,which easily leads to frequent catastrophic winds.The winds can easily cause the vertical concrete transportation equipment—cable crane hoisting bucket to offset,which increases the risk of space conflicts and disasters,additionally,it increases the difficulty of space conflict control.A slight carelessness may cause the hoisting bucket to interact with the dam block surface machinery and materials,etc.,causing huge losses.Therefore,it is of great significance to carry out the calculation and regulation method of space conflict risk for arch dam pouring under wind influence for preventing safety accidents and reducing construction risks.Thus,in view of the construction characteristics of concrete arch dam,according to the progressive levels of spatial resource demand analysis,spatial conflict identification,spatial conflict risk quantification and spatial conflict risk regulation,it carries out the study in the progressive steps.Firstly,the influencing factors of dam pouring are extracted.A spatial three-dimensional coordinate system is established to analyze the spatial movement trajectory of the hazard source in the airspace above the dam surface(cable crane)and the representative disaster-bearing body of the silo surface to be poured(compactor).Through process decomposition,the influence of wind on the operation of the suspension bucket is analyzed,and the falling motion equation of the suspension bucket is constructed to define the impact space.According to the size of pouring silo,the change law of physical working space of vibrating machinery on the dam block surface is analyzed to define the working space.Secondly,a spatial conflict identification mechanism is introduced to distinguish the relative position of the space affected by the lifting bucket and the physical working space of the vibrating machinery on the dam block surface.The topological relationship types of the intersecting working space,such as separation,intersection and inclusion,are proposed.The judgment criteria of spatial conflict topology structure is established to provide critical detection conditions for spatial conflict identification,with calculating the probability of the occurrence of the cable crane/construction machine on the dam block surface in the spatial conflict area.Combined with the occurrence frequency of different wind speeds,the joint probability is used to comprehensively express the risk caused by spatial conflict,and the multiagent system simulation method is proposed to solve the risk caused by spatial conflict.Then,it describes the importance of dam concrete pouring to construction safety and construction period and the current problems.The risk of spatial conflict is regulated by constructing a multi-objective route optimization model with spatial conflict risk,efficiency,operability,and collision risk as sub-objectives.The non-dominating sorting genetic algorithm II(NSGA-II)is used to solve the global optimal route of cable crane under the constraint of spatial conflict risk.Finally,taking BHT Hydropower Station as an example,according to the basic data collected,a simulation model of dam pouring is built to quantify the spatial conflict risk and solve the optimal operation route of cable crane under different working conditions.Based on the discussion and analysis of the quantitative results of risk caused by space conflict and the results of the optimal route of cable crane,the countermeasures for adjusting the cross-working space conflicts of dam concrete pouring are proposed,which provides theoretical support for the safety management in the process of dam concrete pouring.The results show that the calculation method of arch dam pouring space conflict risk and cable crane operation route planning model proposed in this paper have certain guiding significance for reducing the arch dam pouring space conflict risk,reducing safety accidents,and optimizing the cable crane operating route.