Stability Analysis and Support Design Methods for Rock Foundation Pit with Combination of Structural Plane and Karst Cave

Table 2

Calculation of Rankine’s active earth pressure increment.

	Depth (m)	Total active earth force (kN)	Increment of active earth force (kN)	Increment of earth pressure (kPa)
Rankine’s active earth pressure (earth pressure has a triangular distribution)	0	0	0	0
	3	17.76	17.76	11.84
	6	71.03	53.27	35.52
	9	159.82	88.79	59.19
	12	284.12	124.30	82.87
	15	443.94	159.82	106.55
	18	639.28	195.34	130.22
	21	870.13	230.85	153.90
	24	1136.50	266.37	177.58
	27	1438.38	301.88	201.25
	30	1775.78	337.40	224.93