Due to the ignorance of the influence of frozen soil during the design period, the frost damage of subgrade in Datong-Junggar Railway was serious. The improvement scheme of frost damage was researched. However, the research based on the existing project was few, and previous improvement schemes could have an impact on the normal operation of railway system. Datong-Junggar Railway has undertaken the important task of transporting coal resources for China since its normal operation. To ensure normal operation of existing railway, the heating hole scheme was investigated by finite element simulations. The embedding spacing, the heating hole temperature and the embedding depth were analyzed. Based on the simulated results and on-site conditions, the design scheme of the heating hole (embedding spacing: 1.0 m, the heating hole temperature: 30°C and embedding depth: 70 cm) was proposed. Finally, the on-site monitoring in Qianshimen was taken to verify the feasibility of the heating hole scheme. Under the continuous energizing condition, the ground temperature remained basically stable even though the temperature had dropped to −7°C. The research results could enrich the design schemes for frost damage in cold regions from the aspect of ground temperature control.

With the steady development of the development of the western region in China, the construction of mountain highways has developed rapidly, and the soil‐rock mixed filler, as an excellent filler, is widely used in the subgrade filling of mountain highways. Unlike ordinary fine‐grained soil, the source of the soil‐rock mixtures (S‐RMs) is not unique, and the particle size difference is large and the water content is not uniform, resulting in very complicated mechanical properties. But the current highway embankment codes are still mainly established on the fine‐grained soil. It is not fully applicable to soil‐rock filled embankment. Based on soil‐rock filled embankment engineering practice, this research uses a large‐scale direct shear test to research the mechanical characteristics of the S‐RMs with different maximum particle diameters. According to the large‐scale direct shear test of S‐RMs with different maximum particle diameters, the shear displacement vs shear stress curve, shear dilation, and strength characteristics with maximum particle diameter were analyzed. Results demonstrate that whether secondary hardening occurs mainly depends on the normal stress and the maximum particle diameter of the filler. At different maximum particle diameters, the horizontal displacement vs vertical displacement curves of the S‐RMs can be roughly divided into continuous shearing and beginning of shearing and quick dilation. And the shear strength increases with the increase of the maximum particle diameter. Moreover, the cohesion decreases first and then increases with the increase of the maximum particle diameter, and the internal friction angle increases with the increase of the maximum particle diameter. Therefore, some RBs with large particle diameter added to filler can effectively improve the shear strength of the S‐RMs, which may be valuable for realistic engineering.

Affected by the site construction conditions, the measurement passes of the Taihang Expressway K8 + 105 ∼ K8 + 341 (K8 worksite) in the Taihang Expressway did not meet the requirements of data analysis, and the quantity of the control points was insufficient so that the linear correlation between the dynamic deformation modulus () and the vibratory compaction value (VCV) was not strong. Therefore, the target value of VCV cannot be used to diagnose the E_v d compaction quality of soil‐rock filler. This paper analyzes the roller measurement VCV value and in situ measurements E_v d value separately. Results reveal the difference between the VCV mean measured in the last two passes and the standard deviation of the measured VCV mean in the last pass are used as the main basis for the actual compaction quality. In addition, the E_v d mean in the last rolling can be used as an auxiliary judgment basis for the quality control of the compaction.

Spatial distribution orientations of blocks can cause significant errors in the discrete element model (DEM) calculation of soil-rock mixture (SRM). To avoid this error, spherical harmonic (SH) series whose harmonization degrees fixed at 15 were proposed for block reconstruction. This research refers to the case-history of a deep excavation rift valley spanning from the Mabian to Zhaojue section of the Leshan-Xichang Expressway, mainly containing moderately-weathered silty mudstone, in the Leshan City, Sichuan Province, China. The appropriate degree of finite-term SH series is selected by the volume, surface area. 100 blocks were scanned on site, and sphericity and angularity of the blocks were calculated. The sphericity and angularity of 50 reconstructed blocks were considered for the error analysis of SH method. Moreover, stochastic polyhedron method was considered for comparing different block reconstructions. The maximum block placement angle was defined to control the spatial distribution orientations of the blocks. Large scale direct tests were carried. Numerical simulations of large-scale direct shear tests were conducted to study the influence of the spatial distribution orientations of the blocks on the mechanical properties of the SRMs. The results revealed that the finite-term SH series fixed at 15 accurately reflected the shape characteristics and mechanical behaviors of actual blocks. The spatial distribution orientations of the blocks had a minimal impact on the friction angle and cohesion of SRM constructed through the SH method. The SRMs developed via the SH method exhibited marginal variations in contact force and anisotropy index of contact across diverse block placement strategies. The evolution of coordination number was closer when employing the SH method under varied block placement methods. Blocks reconstructed by the SH method, could mitigate errors in DEM calculation caused by the spatial distribution orientations of the blocks.