Abstract: Regarding the groundwater contamination problems caused by leachate leakage from aging domestic waste landfills in heterogeneous composite permeable strata, the vertical barrier engineering practice implemented downstream of Hangzhou Tianziling landfill was taken as an example. Under the coupling of the fault zone and permeable strata, a multi-tiered gradient barrier system was developed by adopting the multi-process coupling seepage prevention technology of “curtain grouting + chemical grouting + self-setting slurry - HDPE geocomposite seepage prevention wall”. In areas characterized by well-developed fault fracture zones and permeable gravel layers, a “curtain grouting + chemical grouting” method was implemented to construct a cutoff curtain. A composite anti-seepage technology featuring the combined effect of “self-setting grout + high-density polyethylene (HDPE) geosynthetic membrane” was adopted for moderately weathered rock strata. Through the innovative integration of construction processes and field implementation techniques, seamless connections of impermeable barriers across heterogeneous geological units were achieved. This approach facilitates a paradigm shift from reactive contamination remediation to proactive risk governance, achieving precise blocking of the leachate migration path and spatial control of groundwater pollution.

Key words: domestic waste landfill, fault fracture zone, vertical cutoff, self-solidifying mortar-HDPE geosynthetic composite cutoff wall, gradient anti-seepage barrier system