Reinforced hot melt pile-soil interface combined type large direct shear test device under curing condition

Abstract

The utility model discloses a combined large direct shear test device for a reinforced hot melt pile-soil interface under a curing condition, and relates to a direct shear device. The utility model aims to solve the technical problem that the influence of the lime curing age on the mechanical property of the reinforced hot melt pile-rib-soil interface is difficult to research at present. Through the design of the shear box and the inner sleeve box, the test piece can be molded and cured in the inner sleeve box, so that the shear test piece does not need to be demolded and cured after being molded, and disturbance damage to an interface in the demolding and remold processes of the test piece is prevented; the maintenance test piece is independently stored and maintained in the inner sleeve box to the target maintenance time and then assembled with the shear box, maintenance of a large batch of direct shear test pieces can be carried out at the same time, the number of needed shear boxes is reduced, meanwhile, the inner sleeve box is made of organic glass materials, the weight of a maintenance test piece mold is greatly reduced, operation is easy and convenient, and cost is low. During loading, the inner sleeve box and the shear box are spliced and then integrally shear, so that the strength requirement of the shear box can be met.

Description

TECHNICAL FIELD

[0001] The utility model relates to a direct shear device. BACKGROUND

[0002] The direct shear test is the most common method for studying the shear characteristics of the pile-soil interface, and the test method is simple and can quickly obtain the shear strength under different normal forces at the interface and the corresponding cohesion and internal friction angle. In the reinforced hot-melt pile roadbed structure disclosed in patent CN201910625553.9, the lime pile is wrapped with geosynthetic material, which artificially forms an interface between the lime pile and the surrounding soil. Since the strength of lime and soil is formed slowly, the effect of curing time on the interface strength parameters needs to be considered when studying the interface. The currently commonly used direct shear test device is assembled by two upper and lower samples during the test, and it is difficult to consider the effect of curing time on the interface strength. SUMMARY

[0003] The utility model is to solve the technical problem that it is difficult to study the effect of lime curing age on the pile-reinforcement-soil interface mechanical characteristics of the reinforced hot-melt pile, and to provide a large-scale direct shear test device for the pile-soil interface of the reinforced hot-melt pile under curing conditions.

[0004] The large-scale direct shear test device for the pile-soil interface of the reinforced hot-melt pile under curing conditions comprises an upper shear box, a lower shear box, an upper inner sleeve box, a lower inner sleeve box, a loading plate 9, and a geotextile 11.

[0005] The upper shear box is a hollow cube structure composed of two opposite first metal plates 2 and two opposite first organic glass plates 3. The upper and lower ends of the upper shear box are open structures.

[0006] The lower shear box is a hollow cube structure composed of two opposite second metal plates 6 and two opposite second organic glass plates 5. The upper end of the lower shear box is an open structure, and the lower end is closed by a bottom plate 10. Two glass pieces 4 are symmetrically arranged on the outer wall of the second organic glass plate 5, and the upper edge of the glass piece 4 is higher than the upper edge of the second organic glass plate 5. A metal clamp plate 7 is arranged on the outer side of one second metal plate 6 near the upper end, and the metal clamp plate 7 is fixed on the second metal plate 6 by a plurality of bolts 8. The size of the lower shear box is the same as that of the upper shear box.

[0007] The upper inner sleeve box is a hollow cube structure composed of four third organic glass plates 1. The upper and lower ends of the upper inner sleeve box are open structures. The upper inner sleeve box is arranged in the inner cavity of the upper shear box and tightly fits around the upper shear box. The upper inner sleeve box and the upper shear box are in sliding connection, and they are of the same height.

[0008] The lower inner sleeve box is completely identical in size and shape with the upper inner sleeve box, is arranged in the inner cavity of the lower shearing box and closely fitted therearound, is in sliding connection with the lower shearing box, and is equal in height to the inner cavity of the lower shearing box;

[0009] The loading plate 9 is a square thin plate, and the side length of the loading plate 9 is smaller than the inner cavity side length of the upper inner sleeve box;

[0010] The upper shearing box is placed directly above the lower shearing box, the first metal plate 2 is above the second metal plate 6, the first organic glass plate 3 is above the second organic glass plate 5, the geotextile 11 is clamped between the upper shearing box and the lower shearing box, the geotextile 11 is a rectangular structure and completely covers the lower shearing box, and one end of the geotextile 11 is clamped between the metal clamping plate 7 and the second metal plate 6.

[0011] The use method of the health condition reinforced hot-melt pile-soil interface combined large-scale direct shear test device is as follows:

[0012] Step one, the test soil is dried, crushed and passed through a 2mm geotextile sieve, water is added to a moisture content of 20%, the mixture is sealed and placed for 24 hours, then placed in the upper inner sleeve box and compacted into a flat shape, and the density is controlled to 1.5g / cm 3 ;

[0013] Step two, the blocky quicklime is completely hydrated and disintegrated by adding water, then dried at 60℃, and mixed with dry soil and water after passing through a 2mm sieve, and the moisture content is controlled to 20%; then placed in the lower inner sleeve box and compacted into a flat shape, and the density is controlled to 1.5g / cm 3 ;

[0014] Step three, the upper inner sleeve box, the geotextile 11 and the lower inner sleeve box are combined from top to bottom, the side walls of the upper inner sleeve box and the lower inner sleeve box are flush, the three are tightly wrapped with a plastic wrap and sealed with adhesive tape, and then placed in a 4℃ refrigerator for temperature control and health care to simulate the environment temperature of the degraded frozen soil after the foundation is pre-melted;

[0015] Step four, after the test piece is finished, the whole is taken out of the refrigerator, the plastic wrap is opened, and the upper and lower shearing boxes are assembled into one (the upper inner sleeve box is arranged in the upper shearing box, the lower inner sleeve box is arranged in the lower shearing box, the upper shearing box is placed directly above the lower shearing box, the first metal plate 2 is above the second metal plate 6, the first organic glass plate 3 is above the second organic glass plate 5, the geotextile 11 is clamped between the upper shearing box and the lower shearing box, the geotextile 11 is a rectangular structure and completely covers the lower shearing box, and one end of the geotextile 11 is clamped between the metal clamping plate 7 and the second metal plate 6), and then placed in a temperature-controlled direct shear instrument for large-scale direct shear test;

[0016] Step five, start the temperature control system of the temperature-controlled direct shear apparatus, control the temperature inside the direct shear apparatus at 4 DEG C, which is consistent with the curing temperature of the test piece, after the temperature reaches the target temperature, continue to control the temperature for 6 hours, after the temperature control is completed, install the loading plate 5 above the direct shear test piece, i.e. place the loading plate 5 in the inner cavity of the upper inner sleeve box, and apply the normal load through the vertical loading shaft of the direct shear apparatus, and control the normal stress to be 100, 200 and 300 kPa respectively;

[0017] Step six, after the normal stress reaches the target value, start the direct shear test and record the shear stress-shear displacement data, and terminate the test after the shear displacement reaches 15%; in this process, the upper and lower shear boxes will slide along a horizontal direction, and the four glass sheets 4 can limit the upper shear box to slide in a fixed direction.

[0018] The beneficial effects of the utility model are as follows:

[0019] 1. The device can perform large-scale direct shear test on the reinforced hot-melt pile-pile reinforcement-soil complex interface, the metal clamping plate 7 arranged on the shear box can fix the geosynthetic material (geotextile or geogrid), so as to study the mechanical properties of the hot-melt pile body material-geosynthetic material-ground soil complex interface under different pile body mix proportions, loading rates, overburden loads and other influencing factors.

[0020] 2. The device is designed with the shear box and the inner sleeve box, the test piece can be formed and cured in the inner sleeve box, so that the test piece does not need to be demolded and cured after being formed, and the disturbance and damage to the interface during the demolding and remolding process are prevented.

[0021] 3. The device fully considers the strength improvement of the lime material and clay interface due to the lime curing period, the curing test piece can be stored and cured in the inner sleeve box alone, and then assembled with the shear box after being cured to the target curing time, a large number of direct shear test samples can be cured at the same time, the number of shear boxes required is reduced, the inner sleeve box is made of organic glass material, the weight of the curing test piece mold is greatly reduced, the operation is simple, and the inner sleeve box and the shear box are assembled after loading, and the shear effect is performed on the whole, so that the strength requirement of the shear box itself is met.

[0022] 4. The device can also be applied to low-temperature controlled freezing direct shear test or curing direct shear test of other pile foundation interfaces in cold regions. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a top view of the upper inner sleeve box of the first embodiment;

[0024] Figure 2 It is a front view of the upper inner sleeve box of the first embodiment;

[0025] Figure 3 This is a front view of the upper clipping box in Specific Implementation Method 1;

[0026] Figure 4 This is a top view of the upper clipping box in Specific Implementation Method 1;

[0027] Figure 5 This is a front view of the lower shear box in Specific Implementation Method 1;

[0028] Figure 6 This is a top view of the lower clipping box in Specific Implementation Method 1;

[0029] Figure 7 This is a side view of the lower shear box in Specific Implementation Method 1;

[0030] Figure 8 This is a top view of the loading plate 9 in the first specific implementation method;

[0031] Figure 9 This is a top view of the combined large direct shear test device for reinforced hot-melt pile-soil interface under the curing conditions of Specific Implementation Method 1.

[0032] Figure 10 This is a side view of the combined large direct shear test device of reinforced hot melt pile-soil interface under curing conditions according to the specific implementation method one. Detailed Implementation

[0033] Specific Implementation Method 1: This implementation method is a large-scale direct shear test device for reinforced hot-melt pile-soil interface combination under curing conditions, such as... Figures 1-10 As shown, it is specifically composed of an upper shear box, a lower shear box, an upper inner sleeve box, a lower inner sleeve box, a loading plate 9, and a geotextile 11;

[0034] The upper shear box is a hollow cube structure formed by two opposing first metal plates 2 and two opposing first organic glass plates 3, with both the upper and lower ends of the upper shear box being open structures.

[0035] The lower shear box is a hollow cube structure formed by two opposing second metal plates 6 and two opposing second plexiglass plates 5. The upper end of the lower shear box is open, and the lower end is closed by a base plate 10. Two glass sheets 4 are symmetrically arranged on the outer wall of the second plexiglass plates 5, with the upper edge of the glass sheets 4 higher than the upper edge of the second plexiglass plates 5. A metal clamp 7 is arranged on the outer side of one of the second metal plates 6 near the top, and the metal clamp 7 is fixed to the second metal plate 6 by multiple bolts 8. The dimensions of the lower shear box are exactly the same as those of the upper shear box.

[0036] The upper inner box is a hollow cube structure enclosed by four third organic glass plates 1, and the upper and lower ends of the upper inner box are both open structures; the upper inner box is arranged in the inner cavity of the upper shear box and tightly adheres to the periphery, and the upper inner box and the upper shear box are in sliding connection, and the upper inner box is in the same height as the upper shear box;

[0037] The size and shape of the lower inner box are completely the same as those of the upper inner box, the lower inner box is arranged in the inner cavity of the lower shear box and tightly adheres to the periphery, the lower inner box and the lower shear box are in sliding connection, and the inner cavity of the lower inner box is in the same height as that of the lower shear box;

[0038] The loading plate 9 is a square thin plate, and the side length of the loading plate 9 is smaller than the inner cavity side length of the upper inner box;

[0039] The upper shear box is placed directly above the lower shear box, the first metal plate 2 is above the second metal plate 6, the first organic glass plate 3 is above the second organic glass plate 5, the geotextile 11 is clamped between the upper shear box and the lower shear box, the geotextile 11 is a rectangular structure and completely covers the lower shear box, and one end of the geotextile 11 is clamped between the metal clamping plate 7 and the second metal plate 6.

[0040] The use method of the health preserving condition reinforced hot-melt pile-soil interface combined large-scale direct shear test device in the embodiment is as follows:

[0041] Step one, the test soil is dried, crushed and passed through a 2mm geotextile sieve, water is added to a moisture content of 20%, sealed and left to stand for 24h for standby, then placed in the upper inner box and compacted into a flat shape, and the density is controlled to 1.5g / cm 3 ;

[0042] Step two, the blocky quicklime is completely hydrated and disintegrated, then dried at 60℃, and then mixed with dry soil and water, with the moisture content controlled to 20%; then placed in the lower inner box and compacted into a flat shape, and the density is controlled to 1.5g / cm 3 ;

[0043] Step three, the upper inner box, the geotextile 11 and the lower inner box are combined from top to bottom, and the side walls of the upper inner box and the lower inner box are flush, the three are tightly wrapped with a preservative film and sealed with adhesive tape, and then placed in a 4℃ refrigerator for temperature control and health preservation to simulate the environmental temperature of the degraded frozen soil after the foundation is pre-melted;

[0044] Step four, after the end of the specimen curing, the whole is taken out from the freezer, the plastic wrap is opened, and the upper and lower shear boxes are assembled into one (the upper inner sleeve box is set in the upper shear box, the lower inner sleeve box is set in the lower shear box, the upper shear box is placed directly above the lower shear box, the first metal plate 2 is above the second metal plate 6, the first organic glass plate 3 is above the second organic glass plate 5, the geotextile 11 is clamped between the upper shear box and the lower shear box, the geotextile 11 is a rectangular structure and covers the lower shear box completely, one end of the geotextile 11 is clamped between the metal clamp plate 7 and the second metal plate 6) and then put into the temperature-controlled direct shear instrument for large-scale direct shear test;

[0045] Step five, turn on the temperature control system of the temperature-controlled direct shear instrument, control the temperature inside the direct shear instrument at 4℃, which is consistent with the specimen curing temperature, after the temperature reaches the target temperature, continue to control the temperature for 6h, after the temperature control is completed, install the loading plate 5 above the direct shear specimen, i.e. place the loading plate 5 in the inner cavity of the upper inner sleeve box, and apply the normal load through the vertical loading shaft of the direct shear instrument, and control the normal stress to be 100, 200 and 300kPa respectively;

[0046] Step six, after the normal stress reaches the target value, start the direct shear test and record the shear stress-shear displacement data, and terminate the test when the shear displacement reaches 15%; in this process, the upper and lower shear boxes will slide along a horizontal direction, and the four glass sheets 4 can limit the upper shear box to slide horizontally in a fixed direction.

[0047] The beneficial effects of the embodiment are as follows:

[0048] 1. The device of the embodiment can perform large-scale direct shear test on the reinforced hot-melt pile-pile reinforcement-soil complex interface, the metal clamp plate 7 provided on the shear box can fix the geosynthetic material (geotextile or geogrid), and the mechanical properties of the hot-melt pile-pile body material-geosynthetic material-ground soil complex interface under different pile body mix proportions, loading rates, and overburden loads can be studied;

[0049] 2. The embodiment can form and cure the specimen in the inner sleeve box through the design of the shear box and the inner sleeve box, so that the shear test specimen does not need to be demolded and cured after forming, which prevents the disturbance and damage to the interface during the demolding and remolding process;

[0050] 3、The embodiment fully considers the strength improvement of the lime material and clay interface due to the lime curing age, and can store the curing test piece in the inner sleeve box for curing to the target curing time, and then assemble with the shear box, which can simultaneously cure a large number of direct shear test pieces, reduce the number of shear boxes required, and the inner sleeve box is made of organic glass material, which greatly reduces the weight of the curing test piece mold, is easy to operate, and can meet the strength requirements of the shear box when the inner sleeve box and the shear box are assembled and sheared as a whole.

[0051] 4、The device of the embodiment can also be applied to low-temperature controlled freezing direct shear test or curing direct shear test of other pile foundation interfaces in cold regions.

[0052] Specific embodiment two: The difference between the embodiment and the specific embodiment one is that the two adjacent side walls in the upper shear box are fixed by bolts. The others are the same as the specific embodiment one.

[0053] Specific embodiment three: The difference between the embodiment and the specific embodiment one or two is that the two adjacent side walls in the lower shear box are fixed by bolts. The others are the same as the specific embodiment one or two.

[0054] Specific embodiment four: The difference between the embodiment and any one of the specific embodiments one to three is that the two adjacent side walls in the upper inner sleeve box are fixed by bolts. The others are the same as the specific embodiment one to three.

[0055] Specific embodiment five: The difference between the embodiment and the specific embodiment four is that the two adjacent side walls in the lower inner sleeve box are fixed by bolts. The others are the same as the specific embodiment four.

Claims

1. A large-scale direct shear test device for reinforced hot-melt pile-soil interface combination under health condition, characterized in that The reinforced hot-melt pile-soil interface combined large-scale direct shear test device under health preserving conditions is composed of an upper shear box, a lower shear box, an upper inner sleeve box, a lower inner sleeve box, a loading plate (9) and a geotextile (11); The upper shear box is a hollow square structure composed of two opposite first metal plates (2) and two opposite first organic glass plates (3). The lower shear box is a hollow square structure composed of two opposite second metal plates (6) and two opposite second organic glass plates (5); the upper end of the lower shear box is an open structure, and the lower end is provided with a bottom plate (10) for closure; two glass sheets (4) are symmetrically arranged on the outer wall of the second organic glass plate (5), and the upper edge of the glass sheet (4) is higher than the upper edge of the second organic glass plate (5); a metal clamping plate (7) is arranged on one side of the second metal plate (6) near the upper end, and the metal clamping plate (7) is fixed on the second metal plate (6) through a plurality of bolts (8); the size of the lower shear box is the same as that of the upper shear box. The upper inner sleeve box is a hollow square structure composed of four third organic glass plates (1); the upper and lower ends of the upper inner sleeve box are open structures; the upper inner sleeve box is arranged in the inner cavity of the upper shear box and tightly fits around, and the upper inner sleeve box and the upper shear box are in sliding connection; the upper inner sleeve box is the same height as the upper shear box. The size and shape of the lower inner sleeve box are the same as those of the upper inner sleeve box; the lower inner sleeve box is arranged in the inner cavity of the lower shear box and tightly fits around, and the lower inner sleeve box and the lower shear box are in sliding connection; the inner cavity of the lower inner sleeve box is the same height as that of the lower shear box. The loading plate (9) is a square thin plate, and the side length of the loading plate (9) is smaller than the inner cavity side length of the upper inner sleeve box. The upper shear box is placed directly above the lower shear box, the first metal plate (2) corresponds to the upper side of the second metal plate (6), the first organic glass plate (3) corresponds to the upper side of the second organic glass plate (5), the geotextile (11) is clamped between the upper shear box and the lower shear box, the geotextile (11) is a rectangular structure and completely covers the lower shear box, and one end of the geotextile (11) is clamped between the metal clamping plate (7) and the second metal plate (6).

2. The reinforced hot-melt pile-soil interface combined large-scale direct shear test device under health condition according to claim 1, characterized in that The adjacent two side walls in the upper shear box are fixed by bolts.

3. The reinforced hot-melt pile-soil interface combined large-scale direct shear test device under health condition according to claim 1, characterized in that The adjacent two side walls in the lower shear box are fixed by bolts.

4. The reinforced hot-melt pile-soil interface combined large-scale direct shear test device under health condition according to claim 1, characterized in that The adjacent two side walls in the upper inner sleeve box are fixed by bolts.

5. The reinforced hot-melt pile-soil interface combined large-scale direct shear test device under health condition according to claim 1, characterized in that The adjacent two side walls in the lower inner sleeve box are fixed by bolts.

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