<p>Slope stability analysis is a fundamental topic in geotechnical engineering. While traditional studies primarily focus on simple slope geometries, the coupled effects of multi-stage irregular slope configurations and hydraulic interactions—ubiquitous in practical engineering—have received limited attention. The mechanisms through which pore water pressure and groundwater level fluctuations influence complex slope stability remain poorly understood. This study proposes a stability analysis model integrating slope geometry and hydraulic effects using the upper bound theorem of limit analysis. By introducing the pore water pressure coefficient (<i>r</i>_u) and groundwater level coefficient (<i>h</i>), energy balance equations were derived via the virtual work principle, and an analytical expression for the safety factor (<i>F</i>_s) was obtained using the strength reduction method. The coupled impacts of slope morphology, pore water pressure, and groundwater level on global/local stability were systematically investigated. Results show that increasing <i>r</i>_u significantly decreases <i>F</i>_s, with the anti-sliding contribution of slope geometry diminishing as <i>r</i>_u rises. A rise in groundwater level (decrease in <i>h</i>) reduces <i>F</i>_s: under <i>r</i>_u = 0.25, <i>F</i>_s under full saturation (<i>h</i> = 0) decreases by up to 31% compared to dry conditions (<i>h</i> = 1). For three-stage irregular soil slopes, when the segment height coefficient, pore water pressure, and groundwater level reach critical thresholds, the slip surface migrates toward the slope face, triggering a transition from global to local failure.</p>