Flow calculation method and engineering application of non-standard triangle weir measurement method for rich-water faults

In the construction and operation of tunnels such as highways, railways, water conservancy and hydropower, and mines, it is inevitable to encounter geological disasters such as collapse and water inrush. The instability and destruction of surrounding rocks and seepage sudden change are the direct causes of water inrush. To find out the source of water inrush and the amount of water inrush in the area of F₈ rich-water faults of Longnan tunnel, the non-standard triangular weir measuring method and the rectangular weir measuring method are used to monitor the flow of F₈ surface upstream and downstream. In this paper, the basic concept of non-standard triangular weir method is put forward, and according to the flow formula of standard triangular weir measuring method and the principle of flow equivalence, the flow formula of non-standard triangular weir measuring method is derived. The rationality of the formula is proved by comparing the theory with the measured data. The results show that the derivation of the flow formula of the non-standard triangular weir measurement method provides convenience for the field flow measurement, overcomes the shortcomings of the application scope of the standard triangular weir measurement method formula, and provides a reliable basis for the analysis of the water inflow in the surrounding rock of the tunnel body in the fault fracture zone.