This　paper　proposes　a　novel　steel　plate-concrete　composite　structure　for　underground　diaphragm　walls,　informed　by　an　analysis　of　the　advantages　and　disadvantages　of　existing　underground　retaining　structures.　Current　research　often　assumes　either　no　stacking　or　symmetrical　stacking,　which　may　impair　the　economic　viability　and　practicality　of　projects.　Consequently,　this　study　investigates　the　deformation　mechanisms　of　underground　diaphragm　walls　subjected　to　various　load　combinations.　This　experimental　research　primarily　analyzes　the　impact　of　two　design　parameters:　different　surcharge　combinations　and　the　varying　thickness　of　steel　plates　L2　on　wall　displacement,　wall　bending　moments,　earth　pressure,　and　soil　settlement.　The　study　aims　to　provide　a　comprehensive　understanding　of　how　these　factors　interact　and　influence　structural　performance.　The　analysis　of　the　test　data　indicates　that,　for　wall　structures,　an　asymmetric　stacking　design　outperforms　symmetrical　stacking　in　terms　of　stress　and　displacement.　The　tests　yield　recommendations　and　conclusions　regarding　the　effectiveness　of　the　two　design　parameters.　Additionally,　a　numerical　analysis　model　was　developed　to　compare　its　differences　and　correlations　with　the　experimental　results,　revealing　a　high　degree　of　consistency　in　the　observed　change　patterns.　This　numerical　model　was　utilized　to　optimize　the　experimental　design　and　outcomes.　The　findings　from　both　the　experimental　research　and　numerical　analysis　provide　foundational　references　and　theoretical　support　for　future　research　and　engineering　design.　©　2025　Institution　of　Structural　Engineers