CN101832993B - Half-mold test box for foundation model test by dynamic tamping method - Google Patents

Abstract

The invention belongs to the technical field of rock-soil engineering, and in particular relates to a semi-module test box for dynamic compaction reinforced foundation model test. The semi-module test box consists of a chute, a fixed cross beam, a bracket, a guide rod, a semicircular model hammer, a limit rod, a fixed corner bracket, a model box, a soil pressure box and an acceleration sensor. The fixed cross beam is welded with a cross rod; and a vertical rod in the bracket is connected with an angle steel above the model box. The chute is fixed on the cross beam; a sliding bolt is embedded into the chute, the upper end of the guide rod is connected with the sliding bolt, and the lower end of the guide rod is suspended; and the guide rod passes through a central hole of the semicircular model hammer, the limit rod is positioned above the model box, the upper end of the limit rod is welded with the cross rod in the bracket, and the lower end of the limit rod is welded with the angle steel on the model box. The model box consists of the angle steel, an organic glass board, side panels, a back board and a bottom board; the soil pressure box is embedded in a soil sample; and the acceleration sensor is placed on the top of the soil sample. The semi-module test box ensures that the internal deformation of the soil under the action of dynamic compaction can be directly and conveniently observed, and can measure related data of dynamic stress and the like.

Description

Half-mold test box for foundation model test by dynamic tamping method

technical field

The invention belongs to the technical field of geotechnical engineering, and in particular relates to a half-mold test box for foundation model tests reinforced by a dynamic compaction method.

Background technique

The dynamic compaction method is a ground reinforcement method pioneered by the French Menard technology company in 1969. The soil is rammed with a rammer to make the soil more compact, and the strength and bearing capacity of the soil are greatly improved. In recent years, the dynamic compaction method has been widely used in foundation treatment projects at home and abroad, and has become one of the main methods for large-area foundation treatment. However, there are still few studies on the reinforcement mechanism of dynamic compaction and the influence of various tamping parameters on the effect of dynamic compaction. Although the dynamic compaction method has developed rapidly, the design and construction of the dynamic compaction method are still in a semi-theoretical and semi-empirical state, and the construction parameters on site still need to be determined through a large number of field tests, lacking the necessary theoretical basis, and there are large blindness and Uncertainty. Through the indoor model test, the reinforcement mechanism of the dynamic compaction method can be studied in depth, and the optimal design method of the dynamic compaction method can be proposed. However, due to the lack of a reasonable dynamic compaction indoor model test device, it is difficult to carry out the indoor model test of the dynamic compaction method, which restricts the dynamic compaction method. The further development and improvement of the law.

Contents of the invention

The object of the present invention is to provide a half-form test box for foundation model test reinforced by dynamic tamping method.

The half-form test box for strengthening the foundation model test proposed by the present invention consists of a fixed bolt 1, a slide groove 2, a fixed beam 3, a support 4, a slide bolt 5, a guide rod 6, a semicircle model hammer 7, a limit rod 8, The fixed angle frame 9, the model box 10, the earth pressure box 11 and the acceleration sensor 12 are composed, and its structure is shown in Fig. 1, Fig. 2 and Fig. 3 . Among them, the fixed bolt 1, the sliding groove 2, the fixed beam 3, the bracket 4, the sliding bolt 5, the guide rod 6, the semicircle model hammer 7, the limit rod 8, and the fixed angle frame 9 form the loading system. Support 4 is the frame structure that is welded by vertical bar 13 and cross bar 14, and fixed cross beam 3 is fixed on the top of cross bar 14; The angle steel 15 is connected and fixed by welding with the fixed angle frame 9; the sliding groove 2 is fixed on the beam 3 through the fixing bolt 1; the sliding bolt 5 is embedded in the sliding groove 2, and the sliding bolt 5 can slide along the sliding groove 2, which can facilitate the installation of different diameters The semicircle model hammer 7 can lift the semicircle model hammer 7 to different initial heights; the upper end of the guide rod 6 is connected with the sliding bolt 5, and the lower end is suspended in the air; the guide rod 6 passes through the center hole of the semicircle model hammer 7 to limit the semicircle model Swing in the falling process of hammer 7, guide rod 6 diameters can be adjusted according to the central hole diameter of semicircle model hammer 7. Limit bar 8 is positioned at the top of model case 10, and limit bar 8 upper end is welded with cross bar 14 in support 4, and the lower end is welded with angle steel 15 on the model box 10; Model box 10 is made of angle steel 15, plexiglass plate 16, side The panel 17, the back panel 18 and the base plate 19 are composed of a plexiglass plate 16, two side panels 17, the back panel 18 and the base plate 19 to form a model box frame, and the surroundings of the model box frame are embedded in the angle steel 15; the earth pressure box 11 is embedded in In the soil sample 21 , the number of earth pressure cells 11 depends on the specific situation; the acceleration sensor 12 is placed on the top of the soil sample 21 .

In the present invention, there are four vertical bars 13 and cross bars 14 in the bracket 4 respectively, forming a frame structure, which is placed on the top of the model box 10 .

In the present invention, there are 12 angle steels 15 in the model box 10, which are respectively located at the top, bottom and middle of the model box frame, and each is 4 pieces.

In the present invention, the semicircle model hammer 7 falls freely along the guide rod 6, and the vertical drop of the semicircle model hammer 7 is guaranteed by the limit rod 8, so as to avoid hitting the plexiglass plate 16.

In the present invention, the front of the model box 10 is a plexiglass plate 16 on which a scale line 20 is drawn, so that the internal deformation of the soil sample 21 can be directly observed, and the degree of sparseness of the scale line can be formulated according to specific tests.

In the present invention, the sliding bolt 5 is embedded in the sliding groove 2 so as to adapt to semicircular model hammers 7 of different diameters.

Working process of the present invention is as follows:

The soil samples 21 are loaded into the model box 10, and the soil samples 21 are buried layer by layer according to actual test requirements, and colored soil samples are set between the soil layers as marking lines. A number of earth pressure cells 11 are embedded in the sample, and an acceleration sensor 12 is installed on the upper part of the sample. The earth pressure cell 11 and the acceleration sensor 12 are connected to an external data acquisition system through wires to collect data. The guide rod 6 is penetrated into the semicircle model hammer 7, and the semicircle model hammer 7 is raised to the height required for the test along the guide rod 6, and then the semicircle model hammer 7 is allowed to fall freely to ram the soil, and can perform multiple times of ramming. During the whole test process, the stress inside the soil sample 21 can be tested by the earth pressure cell 11 ; the internal deformation of the soil sample 21 can be directly read through the plexiglass plate 16 marked with the scale line 20 . By obtaining the internal force and deformation of soil sample 21 under dynamic compaction, the reinforcement mechanism of dynamic compaction can be analyzed, the influence of various tamping parameters on the effect of dynamic compaction can be studied, and an optimal design method for dynamic compaction can be proposed.

Beneficial effects of the present invention:

The greatest advantage of the device of the present invention is that it can directly and conveniently observe the internal deformation of the soil under the action of dynamic compaction, and can measure relevant data such as dynamic stress, which solves the many shortcomings of the existing dynamic compaction method indoor model test device.

Description of drawings

Figure 1 is a front view of the present invention.

Figure 2 is a top view of the present invention.

Figure 3 is a side view of the present invention.

Numbers in the figure: 1 is the fixing bolt, 2 is the sliding groove, 3 is the fixed beam, 4 is the bracket, 5 is the sliding bolt, 6 is the guide rod, 7 is the semicircle model hammer, 8 is the limit rod, 9 is the fixed angle bracket , 10 is the model box, 11 is the earth pressure box, 12 is the acceleration sensor, 13 is the vertical bar, 14 is the horizontal bar, 15 is the angle steel, 16 is the plexiglass plate, 17 is the side panel, 18 is the back panel, 19 is the bottom plate , 20 is the scale line, and 21 is the soil sample.

Detailed ways

The present invention is further described below by way of examples.

Embodiment 1, the length of the angle steel 15 in the model box 10 is 1000 mm, the width is 25 mm, and the thickness is 4 mm. The side panels 17 of the model box 10, the back panel 18 and the base plate 19 are planks with a thickness of 30 millimeters, and the front of the model box 10 is a plexiglass plate 16 with a thickness of 10 millimeters, and the length and width of each panel and the base plate are 1000 millimeters. The surroundings of the model box frame are embedded in the angle steel 15, and are connected with the angle steel 15 by bolts. Graduation lines 20 are drawn on the plexiglass plate 16, and each grid size of the graduation lines is 10 mm×10 mm. Support 4 is welded by 4 vertical bars 13 and 4 cross bars 14, and vertical bars 13 and cross bars 14 are all 1000 millimeters in length, 20 millimeters in outer diameter, the steel pipe of wall thickness 2 millimeters. The four vertical rods 13 in the bracket 4 are located above the model box 10, connected with the angle steel 15 positioned above the model box 10 by bolts, and fixed by welding the fixed angle bracket 9, the fixed angle bracket 9 is 300 mm in length and 20 mm in width , a steel bar with a thickness of 5 mm. The two ends of fixed crossbeam 3 are welded in the middle part of crossbar 14 in support 4. The fixed beam 3 is steel with a thickness of 10 mm, a width of 20 mm and a length of 1000 mm. The sliding groove 2 has a thickness of 20 mm, a width of 30 mm, and a length of 1000 mm; inside the sliding groove 2, a groove with a width of 20 mm and a depth of 5 mm is excavated along the length direction, and the cross section of the entire sliding groove 2 is concave type; the width of the concave opening of the sliding groove 2 is reduced, and the top of the sliding bolt 5 can be embedded in the sliding groove 2, and can slide and be fixed along the sliding groove 2. The cross bar 14 welding in the stop rod 8 upper ends and the support 4, the angle steel 15 welding on the lower end and the model case 10, 4 stop rods 8 are all the smooth steel rods that diameter 5 millimeters, length are 1000 millimeters. Guide rod 6 is smooth steel rod, and diameter is 6 millimeters, and length is 950 millimeters, and the top of guide rod 6 is welded with sliding bolt 5, and the bottom is free end. Semicircle model hammer 7 is semicylindrical, and diameter is 120 millimeters, thickness 30 millimeters, and the center of gravity position of semicircle model hammer 7 is drilled with diameter and is the hole of 6 millimeters, so that the penetration of guide rod 6. The distance between the guide rod 6 and the limit rod 8 is controlled by moving the slide bolt 5 so that the side of the semicircle model hammer 7 is tangent to the limit rod 8 . The model box is filled with soil samples 21, 13 earth pressure cells 11 are embedded inside the soil samples 21, and three acceleration sensors 12 are placed on the top of the soil samples 21. Referring to Fig. 1 to Fig. 3, those skilled in the art can implement it smoothly.

Claims (3)

1. A half-form test box for reinforced foundation model test by dynamic tamping method, consisting of fixed bolt (1), slide groove (2), fixed beam (3), support (4), slide bolt (5), guide rod (6 ), a semicircle model hammer (7), a limit rod (8), a fixed angle frame (9), a model box (10), an earth pressure cell (11) and an acceleration sensor (12), and is characterized in that the fixing bolt (1 ), sliding groove (2), fixed beam (3), bracket (4), sliding bolt (5), guide rod (6), semicircle model hammer (7), limit rod (8) and fixed angle bracket (9 ) to form a loading system, the bracket (4) is a frame structure welded by vertical bars (13) and cross bars (14), the fixed beam (3) is fixed above the cross bar (14); the vertical bars in the bracket (4) The rod (13) is located above the model box (10), connected with the angle steel (15) located above the model box (10) through bolts, and fixed by welding the fixed angle bracket (9); the sliding groove (2) is connected by the fixing bolt (1 ) is fixed on the beam (3); the sliding bolt (5) is embedded in the sliding groove (2), and the sliding bolt (5) can slide along the sliding groove (2), which can facilitate the installation of semicircular model hammers (7) of different diameters, and can Lift the semicircle model hammer (7) to different starting heights; the upper end of the guide rod (6) is connected with the slide bolt (5), and the lower end is suspended in the air; the guide rod (6) passes through the center hole of the semicircle model hammer (7), To limit the swing of the semicircle model hammer (7) during its fall, the diameter of the guide rod (6) can be adjusted according to the diameter of the center hole of the semicircle model hammer (7); The upper end of the position bar (8) is welded with the cross bar (14) in the support (4), and the lower end is welded with the angle steel (15) on the model box (10); the model box (10) is made of angle steel (15), the organic Composed of glass plate (16), side panel (17), back panel (18) and bottom plate (19), organic glass plate (16), two side panels (17), back panel (18) and bottom plate (19) are connected A model box frame is formed, and the surroundings of the model box frame are embedded in angle steel (15); the earth pressure cell (11) is buried in the soil sample (21), and the acceleration sensor (12) is placed on the top of the soil sample (21). 2. according to claim 1, the half-mold test box for reinforced foundation model test by dynamic tamping method is characterized in that the vertical bars (13) and cross bars (14) in the support (4) are respectively 4, forming a frame structure , placed on the model box (10) top. 3. the half-mold test box for strengthening foundation model test by dynamic compaction method according to claim 1, is characterized in that the angle steel (15) in the model box (10) totally 12, is respectively positioned at the model box frame top, bottom and the middle, Each is 4.

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