The　one-phase-low-pH　method　is　a　simple,　efficient,　and　user-friendly　biogrouting　technique　that　can　effectively　improve　the　biomineralization　of　enzyme-induced　carbonate　precipitation　(EICP)　using　free　urease　enzyme.　One　of　the　most　significant　advantages　of　this　method　is　its　capacity　to　effectively　delay　calcium　carbonate　(CaCO3)　precipitation　by　reducing　the　pH　of　the　solution　through　the　addition　of　acid.　This　prevents　bioclogging　during　the　biogrouting　process　and　improves　the　biomineralization　effect.　However,　the　biomineralization　of　the　one-phase-low-pH　based　EICP　method　may　be　influenced　by　the　specific　acid　used.　To　investigate　the　impact　of　acid　type　on　the　one-phase-low-pH　EICP　method　using　crude　soybean　urease　solution　(CSUS),　four　types　of　acids,　including　hydrochloric　acid　(HCl),　nitric　acid　(HNO3),　acetic　acid　(CH3COOH),　and　lactic　acid　(C3H6O3),　were　used　to　adjust　the　pH　of　CSUS.　A　series　of　macroscopic　and　microscopic　experiments　were　conducted　to　evaluate　the　effect　of　acid　type　on　the　onephase-low-pH　EICP　method.　The　results　indicate　that　the　acid　has　an　inhibition　on　the　urease　activity　(UA)　of　CSUS.　Among　the　acids　tested,　HNO3　exhibits　the　most　pronounced　inhibitory　effect　on　the　UA　of　CSUS,　followed　by　HCl,　and　the　least　pronounced　inhibitory　effect　for　CH3COOH　and　C3H6O3　under　the　same　pH　conditions.　Meanwhile,　CH3COOH　and　C3H6O3　could　provide　a　longer　delay　duration　of　CaCO3　precipitation　than　HNO3　and　HCl.　Therefore,　the　one-phase-low-pH　EICP　method　based　on　CH3COOH　and　C3H6O3　can　significantly　improve　the　effective　biocementation　depth　compared　to　that　based　on　HNO3　and　HCl.　Nevertheless,　the　different　types　of　acids　appear　to　have　no　obvious　effect　on　the　polymorph　and　crystalline　of　the　precipitated　CaCO3　crystals.　(c)　2024　Institute　of　Rock　and　Soil　Mechanics,　Chinese　Academy　of　Sciences.　Published　by　Elsevier　B.V.　This　is　an　open　access　article　under　the　CC　BY-NC-ND　license　(http://creativecommons.org/licenses/by-nc-nd/　4.0/).