| dc.description.abstract | Borehole wall stability is the key to the shield tunnel and horizontal directional drilling (HDD) under a sand-pebble layer. Borehole instability will lead to the collapse of the upper ground and damage to adjacent structures. To improve the stability of transportation in highly permeable formations, it is suggested that quartz sand be added to the silicate membrane. Here, different particle sizes (40, 70, 120 mesh) and contents (1%, 2%, 3%, and 4%) of quartz sand were applied to investigate the influence of quartz sand on the properties of silicate slurry and filter cake performance by analyzing the rheological properties, fluid loss, and filter cake properties. The results show that when the particle size is 120 mesh and the content is 2% in the membrane slurry, the quartz sand effectively promotes the filter cake performance. Moreover, the spatial structure formed in the slurry is continuous, and the viscosity, static shear force, dynamic shear force, and flow index of the slurry are within an appropriate range, indicating that silicate slurry with 120 mesh and 2% content quartz sand can make the slurry perform well in the sand-pebble layer. This formulation facilitates the effective formation of the filter cake, reduces fluid loss volume, and maintains borehole stability. | |
