Method for detecting cement dosage in core test sample of cement mixing pile

Abstract

The invention discloses a method for detecting cement dosage in a core test sample of a cement mixing pile, which comprises the following steps: directly mixing a field in-situ soil sample with water content without major changes into cement slurry with the same water-cement ratio during field construction, and preparing the test sample into the standard cylindrical test sample with unconfined compressive strength; placing the test sample in same-level in-situ plain soil for extrusion, sealing and maintenance after molding; carrying out EDTA titration after achieving the preset age, obtaining an attenuation law curve of consumption of disodium EDTA along with the age, and establishing standard curves in all the ages according to the attenuation law curve; and determining the consumption of EDTA in the sample, checking the cement dosage from the standard curve, and finally obtaining the cement dosage in the core test sample of the cement mixing pile. The method has simple operation, accurate detection result, good stability and good repeatability.

Description

technical field [0001] The invention belongs to the intersecting field of basic geotechnical experiment of geotechnical engineering and material engineering dosage detection, and in particular relates to an improved EDTA titration method for cement dosage of a cement mixing pile coring sample. Background technique [0002] The current inspection method of cement mixing piles mainly includes two aspects: one is the sensory inspection of piles, that is, about 7 days after pile formation, the sensory inspection of piles is carried out by detecting the number of piles, the distance between piles, and the pile position. The second is the detection of the quality of the pile body itself, which is divided into the integrity of the pile body, the overall size of the pile body, the uniformity, the compactness, the continuity of the pile body, the strength and the bearing capacity of a single pile. Among them, the quality uniformity detection of the deep mixing pile is judged by visua...

AI Technical Summary

Problems solved by technology

[0005] (1) The operation specification of EDTA titration stipulates that the variation range of moisture content of the sample is 2%, but the variation range of moisture content in the core sample of cement mixing pile sometimes reaches 15%, which does not meet the requirements of the specification

[0006] (2) Due to the differences in sample preparation methods and curing conditions will affect the various processes of cement hydrolysis, hydration and coagulation hardening, indirectly affect the dissolution rate of Ca2+ in NH4Cl solution, thus affecting the amount of EDTA disodium standard solution during detection

[0007] (3) "Code for Testing of Highway Inorganic Binder Stable Materials" (JTJ057-94) stipulates that it is not affected by the age of cement and lime stabilized soil (within 7d), and the accuracy of detection after 7d is difficult to grasp

The cement mixing pile can only be drilled and cored for inspection after 28 days after the construction is completed. Through experiments, it is found that the influence of age has a great influence on the experimental results

Images