Automatic rubbing instrument for measuring plastic limit index based on plastic limit principle

Abstract

The invention relates to a novel portable automatic rubbing instrument which is capable of accomplishing a test for mechanically and automatically measuring a plastic limit index of clay soil through combination of a plurality of assemblies. The automatic rubbing instrument of the invention consists of three main parts, namely a supporting frame, a driving device and a rubbing plate, wherein the supporting frame consists of a base, lateral plates, a top plate, a bottom plate and four brackets; the lower ends of the left and right lateral plates are connected with the base through guide rails, the upper ends of the left and right lateral plates are fixed with the top plate through bolts; the four brackets consist of the guide rails and drive the bottom plate to move vertically; the lower end of the bracket is fixed with the base through a supporting base; the driving device consists of an electromotor, a half-gear transmission shaft, a rack, a horizontal slide guide rail, a double-acting jack and a vertical slide guide rail; the electromotor is connected with the half-gear transmission shaft through a transmission belt; one end of the half-gear transmission shaft is blocked with the rack; the rack is arranged on the left lateral plate; the double-acting jack is adhered below the bottom plate and is fixed with the base; the rubbing plate consists of an upper rubbing plate and a lower rubbing plate; the upper rubbing plate is riveted below the top plate through a bidirectional locking slice; and the lower rubbing plate is arranged in a bottom plate groove and is fixed by a clamping sleeve.

Description

technical field [0001] The invention relates to a rubbing test instrument, in particular to a new type of portable test instrument which can realize the automatic rubbing of test samples and complete the test of measuring the plastic limit index of cohesive soil through the combination of various components. Background technique [0002] The plastic limit index of soil is the most basic index for classifying and naming fine-grained soils. In geotechnical engineering, the accuracy of the plastic limit index is related to the correctness of soil naming, which in turn affects the determination of soil bearing capacity. According to the national standard of the People's Republic of China "Standards for Soil Engineering Test Methods" (GB / T50123-1999), the determination methods for the plastic limit of soil samples less than 0.5mm include the joint determination method of liquid and plastic limit and the rubbing method. Although the domestic joint determination method has the adva...

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Problems solved by technology

Although the domestic joint determination method has the advantages of simple operation and relatively stable test data, it is affected by the roughness of the conical surface of the instrument, the degree of wear of the cone tip, the compactness of the soil sample in the sample cup, and the leveling effect of the soil sample surface. The influence of factors is large, the measured actual data deviates greatly from the real data, and this method is not internationally recognized

The traditional manual rubbing method is favored by engineers due to the accumulation of a large amount of engineering practice experience, but the determination of the plastic limit by the traditional rubbing method is a purely manual operation, which is greatly affected by the experience of the experimenters, which is not good for beginners, and can only be used once. Preparation of a soil strip, complex operation, low efficiency, poor reproducibility of test data, large error

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