Cement mortar containing excavated soil prepared by replacing natural sand with engineering soil, and preparation method therefor and application thereof

A preparation method for a cement mortar containing an excavated soil prepared by replacing a natural sand with an engineering soil, wherein the preparation method comprises the following steps:

• (1) drying the engineering soil to a constant weight at a temperature of 105±5° C.;
• (2) sieving the dried engineering soil into A, B and C groups according to particle sizes;
• (3) putting the engineering soil of the C group obtained in the step (2) into a grinder to grind for 2 times to 3 times, with each grinding lasting for 3 seconds to 8 seconds;
• (4) sieving the ground engineering soil of the C group to obtain a sieved engineering soil;
• (5) mixing the sieved engineering soil obtained in the step (4) with the engineering soil of the B group to form a recycled engineering soil;
• (6) mixing the recycled engineering soil obtained in the step (5) with a sieved natural sand, adding into a mortar mixer, stirring to form a sandy soil mixture, and taking out the sandy soil mixture for later use;
• and
• (7) weighing water, cement, the sandy soil mixture and a water-reducing admixture;
• evenly dividing the sandy soil mixture and the water-reducing admixture into two parts, adding the water and the cement into the mortar mixer, and stirring to form a cement slurry;
• then adding one part of the sandy soil mixture and one part of the water-reducing admixture, and stirring;
• and then adding the other part of the sandy soil mixture and the other part of the water-reducing admixture, and stirring to prepare the cement mortar containing the excavated soil prepared by replacing the natural sand with the engineering soil.