CN206531721U

CN206531721U - A kind of four-bladed vane of the distribution of the dispersive stress in direct shear test

Info

Publication number: CN206531721U
Application number: CN201720171495.3U
Authority: CN
Inventors: 操子明; 杨启航
Original assignee: Anhui University of Science and Technology
Current assignee: Anhui University of Science and Technology
Priority date: 2017-02-24
Filing date: 2017-02-24
Publication date: 2017-09-29
Anticipated expiration: 2027-02-24

Abstract

The utility model discloses the four-bladed vane for designing a kind of distribution of the dispersive stress in direct shear test, mainly it is made up of upper four-bladed vane and lower four-bladed vane, upper four-bladed vane and lower four-bladed vane are welded by two blocks of sharp steel plates of the wide opposite side in identical side, and upper four-bladed vane is identical with the circumscribed circle diameter of lower four-bladed vane, its specific placement location is the upper and lower ends of undisturbed sample, and firmly extrude, four-bladed vane and lower four-bladed vane is set to be submerged in the upper and lower ends face of undisturbed sample completely, it is permeable stone in the upper and lower ends of undisturbed sample, permeable stone, undisturbed sample, upper four-bladed vane and lower four-bladed vane are fixed by upper shear box and down cut box, pushed down with pressurizing piston on top.Add in the soil body after four-bladed vane, it is to avoid during destruction only since edge, effectively alleviated edge and occur stress concentration phenomenon；Meanwhile, connector is not formed in the four-bladed vane insertion soil body up and down, will not thus influence be produced on the size of shear surface.

Description

A kind of four-bladed vane of the distribution of the dispersive stress in direct shear test

Technical field：

The utility model is related to a kind of four-bladed vane, more particularly to the cross that a kind of dispersive stress in direct shear test is distributed Plate, belongs to civil engineering test apparatus clothing arts.

Background technology：

Direct shear test is to determine a kind of conventional, ancient and simplest of native shearing strength to obtain method, has been obtained Extensive use, the key instrument of direct shear test is direct shear apparatus.The principle of direct shear test is, according to Coulomb's law, same soil to be made It is standby that respectively under different normal pressures, horizontal shear is directly applied along fixed shear surface into several patterns, when obtaining it and cutting up Shear stress, as shearing strength τ, then determine soil classifiction index φ and c according to shearing law.Although direct shear apparatus is constructed It is simple and convenient to operate, but the shearing stress distribution on shear surface is uneven, during soil sample failure by shear first since edge, on side Stress concentration phenomenon occurs for edge, is but uniformly calculated still according to stress, this has very big error to actually measured shear stress.

The content of the invention：

Technical problem to be solved in the utility model is in order that the shear stress on shear surface is uniformly distributed as far as possible, to prevent It is only first since edge during soil sample failure by shear, cause that stress concentration phenomenon occurs at edge, the utility model provides a kind of exists The four-bladed vane that dispersive stress is distributed in direct shear test.

The technical scheme that is used of technical problem that the utility model is solved is：Dispersive stress is distributed in direct shear test ten Letter stencil is mainly made up of upper four-bladed vane and lower four-bladed vane, and upper four-bladed vane and lower four-bladed vane are by two pieces of wide opposite sides in identical side Sharp steel plate is welded, and upper four-bladed vane is identical with the circumscribed circle diameter of lower four-bladed vane, and its specific placement location is original state The upper and lower ends of soil sample, and firmly extrude, four-bladed vane and lower four-bladed vane is submerged in up and down the two of undisturbed sample completely End face.It is permeable stone in the upper and lower ends of undisturbed sample, permeable stone, undisturbed sample, upper four-bladed vane, lower four-bladed vane are above cut Cut box and down cut box is fixed, top is pushed down with pressurizing piston.Undisturbed sample is taken with cutting ring, after additional soil is scraped off, Extruded respectively in upper and lower ends with four-bladed vane and lower four-bladed vane, four-bladed vane and lower four-bladed vane is submerged in undisturbed soil examination completely The upper and lower ends face of sample, then undisturbed sample is carefully pushed out.After upper shear box and down cut box are fixed, it is sequentially placed into Isodiametric permeable stone, filter paper, undisturbed sample, filter paper, permeable stone and pressurizing piston, pressurizing piston are used to apply different Normal pressure.Made finally by the four-bladed vane up and down applied to down cut box in horizontal thrust, soil sample by shear box up and down Dislocation separation is firmly produced, at this moment soil sample produces detrusion on the horizontal contact face of upper shear box and down cut box, record The now reading of dynamometer and displacement meter.

This four-bladed vane plays a role to the shearing on inside soil body shear surface.While there is shear stress in edge, Also there is shear stress with the drive of four-bladed vane in the soil of four-bladed vane center section up and down, when this just makes pattern failure by shear not only Since edge, will not occur stress concentration phenomenon at edge.

Brief description of the drawings：

Fig. 1 is the location drawing of four-bladed vane in the utility model.

Fig. 2 is the stereogram of upper four-bladed vane.

Fig. 3 is the stereogram of lower four-bladed vane.

Fig. 4 is the top view of upper four-bladed vane.

Fig. 5 is the top view of lower four-bladed vane.

Label declaration in figure:Four-bladed vane under the upper four-bladed vanes of 1-, 2-, 3- permeable stones, the upper shear boxs of 4-, 5- down cut boxes, 6- Pressurizing piston, 7- dynamometers and displacement meter, 8- undisturbed samples.

Embodiment：

The utility model is described in further detail with reference to the accompanying drawings and examples：

Embodiment：

Undisturbed sample is first taken with cutting ring, now undisturbed sample after additional soil is scraped off, uses ten in cutting ring Letter stencil and lower four-bladed vane are extruded in upper and lower ends respectively, four-bladed vane and lower four-bladed vane is submerged in the upper of undisturbed sample completely Lower both ends of the surface, then undisturbed sample is carefully pushed out.After upper shear box and down cut box are fixed, equal diameter is sequentially placed into Permeable stone, filter paper, undisturbed sample, filter paper, permeable stone and pressurizing piston, pressurizing piston be used for apply different normal direction pressures Power.Finally by applying horizontal thrust to down cut box, upper four-bladed vane and lower four-bladed vane are by upper shear box and down cut box Active force produces dislocation separation, and at this moment undisturbed sample produces shearing on the horizontal contact face of upper shear box and down cut box and become Shape, records the reading of now dynamometer and displacement meter.

The shearing stress distribution that the four-bladed vane is effectively reduced on shear surface is uneven, it is ensured that soil sample failure by shear is more than Since edge, and occurs stress concentration phenomenon from edge.Four-bladed vane does not form connector in the soil body up and down simultaneously, also not The reduction of shear surface can be influenceed.

Claims

1. a kind of four-bladed vane of the distribution of the dispersive stress in direct shear test, mainly by upper four-bladed vane (1) and lower four-bladed vane (2) group Into, upper four-bladed vane (1) and lower four-bladed vane (2) are welded by two blocks of sharp steel plates of the wide opposite side in identical side, and on Four-bladed vane (1) is identical with the circumscribed circle diameter of lower four-bladed vane (2), and its specific placement location is up and down the two of undisturbed sample (8) End, and firmly extrude, four-bladed vane (1) and lower four-bladed vane (2) is submerged in the upper and lower ends face of undisturbed sample (8) completely, It is permeable stone (3), permeable stone (3), undisturbed sample (8), upper four-bladed vane (1), lower ten in the upper and lower ends of undisturbed sample (8) Letter stencil (2) is fixed by upper shear box (4) and down cut box (5), and top is pushed down with pressurizing piston (6).

2. a kind of four-bladed vane of distribution of the dispersive stress in direct shear test according to claim 1, it is characterised in that：Upper ten Letter stencil (1) is identical with lower four-bladed vane (2) profile, towards on the contrary, upper four-bladed vane (1) sharp place downwards, the sharp place of lower four-bladed vane (2) Upwards, its circumscribed circle diameter is identical with undisturbed sample (8) diameter.