Test method for determining uniaxial tensile strength of soil mass

Abstract

The present invention discloses a test method for determining uniaxial tensile strength of soil mass. According to the method, test equipment comprising a sample preparation system, a tension system and a data acquisition system is adopted, wherein the sample preparation system comprises a fixation base, a pressing plate, a sample forming device and a fixation screw, the tension system comprises a three-speed electric scissors instrument and a sample clamper, and the data acquisition system comprises a digital display push-pull force gauge, a dial indicator and a computer. According to the method, the one-time static pressure molding technology is adopted to prepare the sample, such that the weak surface caused by layering compaction sample preparation can be avoided; the sample presents the dumbbell shape, and both ends are adopted as the fixation end, such that the operation is simple, and the connection is firm; the fixation end of the sample and the middle part of the sample are connected through the transition section, such that the influence of stress concentration due to sudden diameter change on the test is avoided; and the digital display push-pull force gauge is connected with the computer, such that the pull force can be real-timely recorded, and the maximum pull force value during sample breaking can be accurately recorded.

Description

technical field [0001] The invention belongs to the technical field of civil engineering testing, in particular to a test method for measuring the tensile strength of soil, which is mainly used for measuring the tensile strength of soil in water conservancy engineering, road engineering and agricultural engineering, etc., and provides reliable engineering design and construction management. data. Background technique [0002] As a main building material, soil is widely used in hydraulic engineering, road engineering and agricultural engineering, and is the main material under pressure. In engineering practice, it is found that the hydraulic splitting of the core wall of the soil embankment, the cracking of the road subgrade, and the tension cracks caused by the sliding of the slope are all related to the tensile strength of the soil. Therefore, the accurate determination of the tensile strength of soil is of great significance to the design, construction and management of t...

AI Technical Summary

Problems solved by technology

For example, for the uniaxial tensile strength test of cohesive soil in the "Soil Engineering Test Regulations" (SDS01-79), the preparation of the soil sample is to use layered compaction, first make a square sample, and then cut it into a cylindrical sample , it is easy to form a weak surface at the delamination, and if the force is unstable or too large in the process of cutting the sample, it is easy to disturb the sample and reduce the strength

At the same time, it is easy to cause the test axis to deviate from the center when cutting the sample, and the force on the sample section is uneven when stretching, and it is difficult to ensure that the tensile force is perpendicular to the cross section of the sample

In addition, the two ends of the sample are fixed to the sample cap by adhesive bonding, and then connected to the stretching instrument. The bonding force between the soil and the adhesive is very small, and the rough surface of the sample reduces the bonding. The area of ​​the surface, so this method is not easy to fix the connection surface firmly, and it is easy to disconnect from the cemented surface when stretching

More importantly, when stretching, the tensile load is applied step by step. When calculating the tensile stress, the average value of the two loads before the specimen is damaged is taken as the load value at the time of fracture. This method cannot accurately determine the specimen. Maximum tensile force at break

Due to the influence of the above factors, there is a large error in the measured tensile strength value of the soil.

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