A Calculation Method of Basement Load Applicable to Tunnel Crossing Composite Ground

Abstract

The invention discloses a base load calculation method suitable for tunnels crossing composite strata, which belongs to the technical field of tunnel construction, wherein a mechanical model of the sliding line field between tunnels passing through composite strata and composite strata is established, and according to the composite stratum soft and hard soil The positional relationship between the layer boundary line and the tunnel centerline can accurately and quickly determine the width of the slip zone in the hard soil layer, and realize the calculation of the base load of the tunnel passing through the composite layer. The base load calculation method applicable to tunnels passing through complex strata of the present invention has a simple derivation process, can effectively realize the calculation of base load when the tunnel structure passes through composite stratum, and ensures that the calculation result of the tunnel base load is closer to the measured value and more in line with The actual stress state of the tunnel located in the composite stratum provides an accurate and reliable calculation method for the base load when the tunnel passes through the composite stratum, which ensures the safety of tunnel construction and operation. It is scientific and has good application prospects and promotion value. .

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a base load calculation method suitable for tunnels passing through complex strata. Background technique [0002] With the need for large-scale and deep-layer construction of traffic tunnels in my country, the cross-section of tunnel construction increases and the buried depth increases. There are more and more cases of tunnel construction encountering complex strata. For example, in recent years, a large number of tunnel projects constructed in the Yangtze River, the Pearl River Basin, and the southeast coast in my country have repeatedly encountered upper-soft and lower-hard composite strata. Sand-shale siltstone composite strata with great differences in hardness; another example is the Shiziyang Tunnel of the Guangzhou-Shenzhen-Hong Kong Express Rail Link, which successively traverses soft soil, composite strata with uneven hardness and softness, and fu...

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Problems solved by technology

[0004] The above method can satisfy the calculation of surrounding rock pressure to a certain extent for tunnels passing through ordinary homogeneous strata; however, for tunnels passing through compound strata, due to the differences Using the corrected method to simplify the composite stratum equivalently to a homogeneous stratum to calculate the surrounding rock load will lead to large design errors, resulting in improper reinforcement design of the tunnel structure, and affecting the safety and stability of the tunnel structure design.

At the same time, when the tunnel passes through the composite stratum, the upper part of the tunnel is often affected by the soft soil layer, while the middle and lower part of the tunnel is usually affected by the hard soil layer. For the soft soil layer in the upper part of the composite stratum, it is usually more accurate to use the existing load calculation method Simulation and calculation can be realized accurately. For example, by using the “Calculation Method for Vault Load of Shield Tunnel in Composite Stratum” disclosed in the existing patent CN 106529150, the simulation calculation of the surrounding rock load at the top of the tunnel can be realized to a certain extent, and the vertical load at the top of the tunnel can be obtained. However, there is no reasonable calculation method for the load calculation of the hard soil layer in the middle and lower part of the tunnel, so that the load of the tunnel base surrounding rock on the tunnel structure cannot be calculated more accurately, which affects the surrounding rock load of the tunnel structure The accuracy and comprehensiveness of the calculations have caused great limitations in the design of the tunnel structure

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