The invention discloses a front-supporting and rear-pulling type foundation pit
support system and a construction method thereof. The foundation pit
support system comprises a support
pile, a capping beam, a front-supporting type grouting steel
pipe pile, and a rear-pulling type grouting steel
pipe pile; the support pile is vertically constructed in a soil body to form a foundation pit support; the capping beam is arranged on the support pile; the front-supporting type grouting steel
pipe pile is obliquely buried in the soil body in a foundation pit, the front-supporting type grouting steel pipe pile is anchored on the capping beam, and
grout is injected into a pipe section, below the elevation of the bottom of the foundation pit, of the front-supporting type grouting steel pipe pile; and the rear-pulling type grouting steel pipe pile is obliquely buried in a soil body outside the foundation pit, the rear-pulling type grouting steel pipe pile is anchored on the capping beam,
grout is injected into the whole rear-pulling type grouting steel pipe pile, and the rear-pulling type grouting steel pipe pile and the front-supporting type grouting steel pipe pile are alternately distributed. According to the
system and the construction method thereof, the arrangement density of the front-supporting type grouting steel pipe piles in the length direction of the support pile can be reduced, the reliability, stability, safety and overall strength of the
support system are improved, and the excavation difficulty of earth beside the foundation pit is reduced.