what's a good way to handle generic db conn logic in dal/repo layer?

I'm developing a repo layer with several different repos like UserRepository, ReportRepository, etc. The connection string will be injected through the constructor of the repo. This pattern will be implemented consistently for all repos. Is there a way I can implement this logic generically without having to repeat this implementation for each repo? Each repo currently implements a corresponding interface. For example, UserRepository : IUserRepository. Is there a pattern you normally use to avoid the duplicate code? I could use abstract classes but I'm wondering if that would be too heavy. I've always seen repo classes implementing interfaces in past solutions I've worked on