关键词: 气压深松, 犁底层, 高压气体, 裂隙扩展

Abstract: Pneumatic deep loosening is a new deep loosening technology, which works by injecting highpressure gas into the bottom layer of the plow to create cracks and achieve deep loosening operations. Compared to traditional mechanical deep loosening, it has the characteristics of good deep loosening effect, less soil movement, and difficulty in changing the structure of the plow layer. In order to obtain and analyze the crack propagation characteristics during air pressure subsoiling, an indoor simulation experiment was conducted based on the analysis of the theoretical model of crack propagation. The results showed that the soil surface rose significantly during air pressure subsoiling, and the crack propagation mechanism conformed to the lifting and tensioning mechanism. When the unit weights of the plow bottom are 1.4 g/cm3, 1.6 g/cm3 and 1.8 g/cm3, under an air pressure of 1.8 MPa, the maximum radius of soil crack propagation is 0.55 m, with a maximum width of the crack of 3.23 mm, 9 mm and 8.13 mm, respectively. The unit weight of the plow bottom had an obvious but not positive correlation with the crack propagation width. The crack width decreased when the distance from the gas injection point increased. The experimental result was consistent with the theoretical analysis that crack propagation is a coupling of three processes: air pressure attenuation, gas leakage in soil, and soil displacement.

Key words: air pressure subsoiling, plow bottom, highpressure gas, crack propagation