In order to calculate the rock-socketed depth of rock-socketed piles, the failure characteristics of rock outside piles and the horizontal force and bending moment on the top of bedrock should be taken into account. According to horizontal ultimate bearing characteristics of rock-socketed pile, a simplified analysis model of rock-socketed depth calculation was established. Based on the Hoek-Brown strength criterion and static balance principle, a theoretical calculation formula of rock-socketed depth of rock-socketed piles was deduced with the consideration of horizontal force and bending moment at the top of bedrock. Comparison and analysis of an engineering example showed that values of rock-socketed depth calculated by theoretical formulas are closer to the method of codes. And then the influences of horizontal load, pile diameter, rock uniaxial compressive strength and rock mass rating indexRMRon rock-socketed depths were discussed. The results showed that the rock-socketed depth increases linearly with the increase of horizontal force, non-linearly with the increase of bending moment, and decreases non-linearly with the increase of pile diameter, rock uniaxial compressive strength and rock mass rating indexRMR. At the same condition, when pile diameter increases from 1.0 m to 2.0 m and 3.0 m, rock-socketed depth decreases by 32% and 44%, respectively. When rock uniaxial compressive strength increases from 15 MPa to 30, 45 and 60 MPa, rock-socketed depth reduces by 44.4%, 59.7% and 67.6%, respectively. When the value of rock mass rating indexRMRincreases from 30 to 45, 60 and 75, rock-socketed depth reduces by 48.9%, 72.3% and 84.2%, respectively. Rock mass rating indexRMRhas a significant effect on rock-socketed depth. If the value of rock mass rating indexRMRis more than 85, the rock-socketed depth will less than 1.0 m. When determining the optimum rock-socketed depth of actual rock socketed piles, the strength and quality of rocks and pile diameters should be considered comprehensively.
