## 1 Introduction
Field monitoring studies demonstrated that base grouting and curtain grouting have significant engineering value for the rapid construction of tunnels in high-water-content loess. The New Austrian Tunneling Method (NATM), based on the theoretical foundations of tunnel engineering experience and rock mechanics, combines bolt support and shotcrete as the primary support measures. Its aim is to mobilize and utilize the self-supporting capacity of the surrounding rock, provide timely support and enclose the surrounding rock, and employ dynamic monitoring and measurement to achieve safe, economical, and efficient construction results [12; 13; 14]. The characteristics of the NATM are mainly embodied in its timeliness, enclosure, adhesiveness, and flexibility. As a flexible support method, bolt support can adapt to the deformation of the surrounding rock, significantly reinforce unstable surrounding rock in loess tunnels, improve the elastic resistance of the surrounding rock, enhance the cohesion and internal friction angle of the surrounding rock and soil mass, and provide necessary support force to effectively control local deformation of the soil mass. This helps maintain the stability of the surrounding rock after tunnel excavation [15; 16; 17; 18; 19; 20]. However, water enrichment in the surrounding rock induced by excavation disturbances not only reduces the strength of the surrounding rock but also weakens the effectiveness of the system bolts, leading to large deformations in the surrounding rock. Some researchers have suggested replacing system bolts with locking foot bolts [21; 22; 23]. Effectively addressing the issue of water enrichment in Ioess surrounding rock induced by excavation disturbances while fully leveraging the suspension, reinforcement, and composite beam strengthening effects of bolts has become an important problem that researchers need to solve. To address these issues, researchers have conducted exploration and studies in aspects such as novel support structures, deep hole grouting, and surrounding rock dehydration. [PERSON] [24] addressed the limitations of current support efficiency in Ioess tunnels and proposed a novel Steel-Concrete Composite Support System (SCCS). A numerical analysis was conducted to verify that this new support system offers higher practicality and flexibility in bearing more variable loads and handling large deformations of the surrounding rock during Ioess tunnel construction. Based on the New Austrian Tunneling Method (NATM) concept, [PERSON] [25] and others proposed a tunnel active-passive collaborative control method based on excavation compensation theory. They developed new high-prestness compensation materials and experimentally studied the high-prestness compensation effect and the tunnel active-passive collaborative control mechanism. [PERSON] [26], based on the deformation and failure characteristics of weathered surrounding rock and engineering practice, proposed a coupled support scheme of \"pre-grouting + bolt-shotcrete support + inverted arch structure + U-shaped steel + high and low-pressure deep-shallow hole grouting\". This provides an engineering reference for the support and reinforcement of weak surrounding rock. [PERSON] [27] studied the relationship between the mechanical parameters of surrounding rock and water content through geotechnical tests and proposed a dehydration technology for tunnels in aqueous strata. Relying on engineering practice, [PERSON] [28] revealed the mechanism and causes of water intush through field monitoring and numerical simulation analysis. They proposed measures combining dehydration with emergency replenishment, providing a reference for the prevention and control of water intush accidents in underground engineering. Due to the hygroscopic, expansive, and soil gelation properties of lime, [PERSON] [29] studied the physicochemical properties and indicators of lime and fly ash for stabilizing Ioess. Based on the experimental results, they revealed the mechanism of their effects.