Long-distance large-diameter water pipeline networks in cold and arid regions are faced with severe challenges. Poor thermal insulation is provided by the original soil backfill. High costs are caused by deep burial requirements. Large carbon emissions are produced by traditional cement-based foamed concrete. A basalt fiber foamed concrete (BF-CCG-SCFC) is developed to solve these problems. This material is designed for the "safe shallow burial" of pipelines. A low-carbon foamed concrete matrix was prepared. Part of the cement was synergistically replaced by calcined coal gangue and silty clay. Chopped basalt fibers were introduced into this matrix. A three-dimensional reinforcement network was constructed by these fibers. Different water-binder ratios and fiber content gradients were set. Macroscopic mechanical degradation tests and thermal evolution tests were systematically performed under freeze-thaw cycles. Engineering calculations for trench soil covering were also conducted. The optimal water-binder ratio of the plain matrix is determined to be 0.45. The molding quality of the matrix is well coordinated with the internal pore structure at this ratio. Good basic frost resistance is exhibited by the matrix. The optimal content of basalt fibers is found to be 1.0%. The propagation of frost heave cracks is effectively suppressed by the bridging and pull-out energy dissipation mechanisms of the fibers. After 35 freeze-thaw cycles, the BF1.0 group exhibited the highest residual compressive strength among all fiber-content groups, reaching 3.9 MPa, with a strength loss rate of 15.2%. The thermal conductivity is kept relatively stable. Internal structural defects are triggered by the physical agglomeration of fibers at a fiber content at or above 1.5%. A significant decrease in bearing capacity is caused by these defects. The structural reliability is confirmed by the shallow burial mechanical model calculations. The composite foamed concrete backfill layer with the optimal mix proportion is utilized in this evaluation. Under the coupled effects of soil static load, vehicle live load, and extreme frost heave force, the load-bearing safety factor satisfies engineering requirements. This material achieves a synergy of low thermal conductivity, freeze-thaw resistance, and load-bearing performance, providing a material foundation and theoretical basis for the safe shallow burial and low-carbon backfilling of water delivery pipelines in cold and arid regions.