A Test Method for Load Strength Equivalent Area of ​​Soft Rock Point Considering Weathering Degree

Abstract

A point load strength equivalent area test method considering the degree of weathering of soft rock. The main methods are: A. Sample preparation: Take the upper and lower points near the center of the sample as the loading point, measure and record the average width of the smallest section of the sample and the spacing between the loading points. The ratio of the spacing between the loading points and the average width is 0.3-1.0; B. Point load strength test: after the test, the failure section runs through the entire sample and passes through two loading points is an effective test; C. Repeat A-B operation until the number of valid tests is greater than or equal to 10; D. Sample Calculation of point load strength: The point load strength I of the sample of the nth effective test is obtained from the following formula s n , I s n =P n / (ψW n D n ); E. Calculation of point load strength of weathered soft rock: the point load strength I of each time s n The maximum value, the second maximum value, the minimum value and the second minimum value are removed, and then the remaining point load strength I is calculated. s n the average value of . The point load strength value of weathered soft rock measured by this method is more reliable and accurate.

Description

technical field [0001] The invention relates to a point load strength equivalent area test method considering the weathering degree of soft rock. Background technique [0002] Uniaxial compressive strength is an important indicator of rock strength classification and rock mass weathering zoning, which must be obtained through uniaxial compressive strength tests in the laboratory. However, samples for uniaxial compressive strength usually need to drill cores on site, and then transport them to the laboratory for cutting and grinding; the sample preparation process is difficult and complicated. For rocks that are weak, severely weathered, and have well-developed joints, it is difficult to measure the strength by standard rock test methods because the complete core cannot be taken out normally or processed into a standard sample. [0003] Facing this problem, the International Society of Rock Mechanics (ISRM) has formulated a point load strength test method. The sample is plac...

AI Technical Summary

Problems solved by technology

But for soft rocks, the actual failure section will coincide with the weak section near the two loading points, but the weak section often does not coincide with the minimum section, and the actual failure section usually deviates from the minimum section, that is, the actual failure section is often larger than Minimum cross-sectional area, measured point load strength I s The calculated value is too large; and as the degree of weathering increases, the deviation of the weathered soft rock increases, and the measured point load intensity I s It is unreliable and inaccurate as a basis for rock strength classification and rock mass weathering zoning