The invention discloses a method for determining in situ injection repair
diffusion radiuses of contaminated soil and underground water. According to the method, points are distributed according to a triangle method,
pitch-row is designed to be perpendicular to the flowing direction of the underground water, array
pitch is in the flowing direction of the underground water, and the flow expansion of a repair
reagent in the underground water within the reaction
effective time is taken into account. The method comprises three steps: firstly,
observation method: the repair
reagent and a definite proportion of
bromide ion serving as tracers are simultaneously injected into an aqueous stratum in the condition of
high pressure whirl spraying injection. The
diffusion of the
reagent is judged by observing the phenomena of
grout return and
grout leaking between adjacent injection points; secondly,
bromide ion tracer method: after the completion of injection, underground
water depth setting rapid sampling is performed, the concentration of the tracers is rapidly detected in field, and the concentration of the
bromide ion in the underground water is compared with a background value; thirdly, bromide ion tracer method and
observation method: the optimum
diffusion radiuses are determined through synthetic judgment. The method is applied to
optimal design of diffusion radiuses and hole arrangement parameters and monitoring of injection effect in soil and underground water in situ injection tests and repair construction.