Earth　pressure　balance　(EPB)　shield　tunneling　in　coastal　silty　clay　strata　often　faces　the　problems　of　clogging　on　the　screw　conveyor　or　the　belt　conveyor　due　to　lumps　of　clay　soils　formed　because　of　the　large　cohesion　of　clay　particles.　Soil　conditioning　using　common　foaming　agents　is　not　enough　to　alleviate　the　problem.　Therefore,　the　novel　dispersed　foaming　agent　was　studied　in　this　work　using　performance　and　orthogonal　compound　tests.　The　foam　microstructure　was　observed　using　an　electron　microscope　to　analyze　the　evolution　mechanism　of　bubbles　for　different　additives.　Both　laboratory　and　in　situ　tests　were　carried　out　to　assess　the　effectiveness　of　the　novel　dispersed　foaming　agents.　The　testing　results　showed　that　50　vol.%　is　an　optimum　foaming　injection　ratio　to　improve　rheological　properties　and　undrained　shear　strength　of　silty　clay　to　avoid　the　unnecessary　waste　of　conditioning　materials.　The　half-life　time　(T1/2)　and　foam　expansion　ratio　(FER)　of　novel　foaming　agents　using　the　formation　ionic　solution　as　the　solvent　increased　due　to　existing　hydrophilic　polar　groups　based　on　undisturbed　soil　samples　taken　from　a　Xiamen　Metro　construction　site.　It　was　shown　that　acids,　alkalis,　and　salt　ions　had　little　effect　on　the　FER　and　T1/2　of　foaming　agents　(Foams　A　and　B)　using　the　macromolecular　dispersant.　The　variations　in　the　plasticity　index　were　similar　to　those　of　the　liquid　limit　for　the　muck　conditioned　using　dispersed　foaming　agents　with　sodium　citrate,　sodium　bicarbonate,　and　sodium　chloride　at　a　concentration　of　0.1　wt%.　Sodium　bicarbonate　had　the　most　significant　impact　on　the　foaming　agents＇　anticlay　effect.　Compared　with　commercial　and　house-made　foaming　agents　of　the　Fuzhou　Metro　project,　the　muck　was　effectively　conditioned　by　Foams　A　and　B　based　on　the　slump　and　temperature　values.　In　addition,　the　average　cutter-head　torque　was　reduced　by　about　250　kN·m.　The　amount　of　foaming　agents　used　was　reduced　by　about　18.6%　and　12.9%　on　average　in　the　two　testing　sites,　respectively.　©　2023　American　Society　of　Civil　Engineers.