The weak surrounding rock has the characteristics of easy softening, poor integrity, low mechanical strength, etc., which makes it easy to induce different degrees of deformation and damage under excavation disturbance and then seriously affects the stability of the tunnel. Carrying out soft rock tunnel deformation prediction research and designing the supporting structure according to the predicted value is of great significance to engineering construction and design. Based on the grey theory, the large deformation of the vault, shoulder, and waist of the soft rock tunnel are predicted, and then the specific bolt support is designed in the maximum predicted value (Smax·R) area. The control effects of different bolts, spacing (d), length (L) on the maximum displacement (Smax·M), and maximum stress (σmax·M) the surrounding rock are analyzed by numerical simulation. Results show that the gray model has high prediction accuracy, the best prediction time is one week, and the maximum error is only 2.99%; with the decrease in d, resin bolt support has a significant supporting effect compared with mortar bolt support, with Smax.M and σmax·M reduced by 64.38% and 10.35%, respectively; as the L of bolt increases, compared with the mortar bolt support, the resin bolt support has a more obvious restraining effect on the surrounding rock deformation, and Smax·M and σmax·M are reduced by 28.20% and 10.00%, respectively; when 4.5 m < L < 6.0 m and 0.6 m < d < 0.7 m, resin bolt support should be adopted; in other ranges, mortar bolt support or resin bolt support has a less significant difference in controlling surrounding rock deformation.

In the construction of tunnels located in the dolomite area, the problems caused by the blockage of the drain pipe (ditch) crystallize one after another. The blockage of the drain pipe (ditch) is one of the potential factors for the leakage of water in the tunnel. Therefore, it is of great engineering significance to find out the factors and mechanisms of crystallization of the dolomite tunnel drainage system. In this paper, the crystallization mechanism and crystal characteristics of the mixed solution of dolomite tunnel drainage system are analyzed based on geological investigation, water quality testing, crystal structure, etc., the causes of crystalline blockage of drainage pipes are analyzed by combining indoor model tests and crystallization breaking tests, and finally, the optimization suggestions of the drainage system are proposed. The results show that the water samples of the dolomite tunnel drainage pipeline belong to the mixed solution of multi-ions, the cations are Ca2+, Mg2+, Al3+, etc., and the anions are CO32−、HCO3−、SO42−, etc. Among them, the mass fraction and concentration of Ca2+, Mg2+, Al3+ are relatively high., while the mass fraction and concentration range of Fe3+、Cu2+、Zn2+、Ba2+ are approximately 0; the crystal powder contains Cl, O, S, K, Ca, Mg, Al, Na and other elements, and the content of Ca, Mg, Al In comparison, Ca is more, Al is less, and Mg is between the two; after the evaluation of the degree of crystallization blockage, it is found that the degree of blockage of the transverse drain pipe per linear meter is higher, the circular drainage pipe is lower, and the longitudinal pipe is between the two. The crystal removal effect is more significant with the increase of the ultrasonic vibration frequency. It is found that the optimal removal frequency is 50 kHz, and the optimization suggestion of the drainage system is given in combination with the "V"-shaped pipeline arrangement.

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The Huo-Sha Tunnel of Guiyang Metro Line 1 in China, which runs from the Guiyang Railway Station to the Shachong Road Station, passes through the railway station platform closely. The minimum distance between the vault and the pile foundation is only 2.19 m. The geology is complex, and the settlement control requirements for the oblique sections, platforms, station buildings, pile foundations, and existing buildings are remarkably strict. Comprehensive measures of “super pipe shed support, surrounding rock reinforcement, inverted arch grouting, and lining strengthening are strictly adopted” to prevent the influence of construction on the operation of station buildings and in-service railways, high-speed railways, and other buildings. It also analyzes the changing laws of the existing building subsidence, subgrade settlement, station longitudinal displacement variation, and the development trends of lining safety, stability, eccentricity, compression types, and internal force of the lining. The following results are presented. The Huo-Sha Tunnel is gradually excavated. The roadbed settlement of the Guiyang Railway Station platform gradually increases but does not exceed the existing railway deformation control standards for the subsurface excavation section. The longitudinal distribution of the existing railway settlement is approximately a normal curve after the construction of the secondary lining. This result is consistent with the law of the surface settlement trough proposed by Peck, and the range is between −50 m and 50 m. The stress of the lining is mainly concentrated at the arch waist and the vault, the compression types include large and small eccentric, the axial force value gradually increases symmetrically from the vault to the arch footing, the maximum axial force appears at the arch footing, and all control indicators meet the corresponding control standards. The subgrade settlement of the skew section meets the deformation control standards of the existing railway of the subsurface excavation sections after the stabilization of the secondary lining deformation.