CN203490129U - Inner load test device for post-grouting of pile tip - Google Patents

Abstract

The utility model relates to a load test device for post grouting at the pile end, which comprises a load box, a reaction force device, a soil pressure device, and a pile body pressure device; the reaction force device comprises a chassis, a connecting rod and a reaction force frame ; The lower end of the connecting rod is fixedly connected to the chassis, and the upper end of the connecting rod is connected to the reaction frame, and an adjustment structure for adjusting the height of the reaction frame is provided between the connecting rod and the reaction frame; the load box is arranged on the chassis, and the soil Both the body pressurizing device and the pile body pressurizing device are arranged between the load box and the reaction force frame. The device discloses and overcomes the traditional problem that the post-grouting indoor load test of pile ends cannot be carried out indoors. And it produces the following beneficial effects: it can simulate the force condition and bearing mechanism of the grouting group piles in the indoor experiment, and can simulate single piles and pile groups, piles of different depths and different distances, and has strong adaptability and multiple functions.

Description

A pile end post-grouting indoor load test device

technical field

The utility model relates to an indoor load test suitable for pile end post grouting, in particular to an indoor load test device for pile end post grouting.

Background technique

With the vigorous development of the construction industry, bored cast-in-place piles have been widely used in the construction industry due to their convenient construction. type of use function. In the 1960s, the post-grouting process appeared in the pile end and pile side of the pile type, which made up for the insufficient bearing capacity of the pile type, and the application of this technology has been recognized by geotechnical engineering. However, due to the relatively short rise time of this technology, although many experiments have been done in actual engineering and some progress has been made, many theories are still far from perfect, especially in the load test. On the one hand, because the test conditions are not available in the project, only the static load test of the single pile is done, but in the actual project, most of the piles are often done, the force status and bearing mechanism of the grouted single pile and the grouted pile group There are certain differences, so other research methods are particularly important; although finite element numerical calculation can simulate some conclusions that cannot be obtained in engineering, there are great differences in modeling, design parameters, modeling and boundary conditions It is far from the parameters in the actual project, which leads to the simulated results deviate from the reality. Therefore, many indoor tests are particularly important. In this case, the design of the model for indoor static load tests can analyze the behavior of single piles and pile groups under different stresses, and at the same time can analyze different pile lengths, different pile diameters, and different piles. Pile spacing, forces under different soil layers and different sizes of grout bubbles.

Contents of the invention

The utility model aims at the problem of the current pile static load test, and proposes an indoor load test device capable of carrying out the static load test of post-grouting of pile ends indoors.

A pile end grouting indoor load test device, characterized in that it includes a load box, a reaction device, a soil pressurization device, and a pile body pressurization device; the reaction device includes a chassis, several connecting rods and a reaction force frame; the lower ends of the plurality of connecting rods are fixedly connected to the chassis, the upper ends of the plurality of connecting rods are connected to the reaction force frame, and an adjustment structure that can adjust the height of the reaction force frame is provided between the connecting rods and the reaction force frame; The load box is arranged on the chassis, and the soil pressurizing device and the pile body pressurizing device are both arranged between the load box and the reaction frame, and press against the reaction frame respectively. The load box is a cubic box with an open upper end. During the load test, soil is filled in the load box. The soil pressure device is used to adjust the pressure of the soil in the load box to adjust the soil weight. The soil weight was once called soil bulk density. It is the gravity per unit volume of soil; at least one pile is set in the soil, and the pile pressure device applies pressure to measure the bearing capacity of a single pile or multiple piles.

The reaction frame includes two cross-shaped reaction rods, and the two ends of the reaction rods are respectively provided with through holes.

The adjustment structure includes an adjustment bolt that is penetrated in the through hole and rotatably connected with the reaction rod. The adjustment bolt is provided with an internal thread hole, and the upper end of the connecting rod is provided with an external thread. The external thread at the upper end of the connecting rod The threads cooperate with the internally threaded holes of the adjusting bolts.

The adjusting bolt includes a connecting head and a positioning head, and the positioning head is detachably connected in the connecting head.

The connecting head has an annular connecting portion and a clamping portion, the clamping portion is located at one end of the connecting portion and protrudes radially outward, and the other end of the connecting portion is provided with a counterbore; the The positioning head includes a sleeve with a through hole and a shoulder at one end of the sleeve. The outer circumference of the sleeve is provided with external threads, and the wall of the counterbore is provided with external threads that are compatible with the sleeve. The diameter of the through hole of the sleeve is larger than the bottom diameter of the internal thread hole.

The adjusting bolt includes a connecting head and a positioning ring, the connecting head has an annular connecting portion and a clamping portion, the clamping portion is located at one end of the connecting portion and protrudes radially outward, and the positioning ring is clamped on the the other end of the connection. The outer surface of the ring-shaped connection part is provided with two guide grooves along the axial direction and two ring grooves extending along the same circumferential direction of the connection part. Each guide groove communicates with each ring groove. The positioning block protruding inwards, when the positioning ring is set on the connecting part, the two positioning blocks can be set in the guide groove at the same time, and then the positioning ring is rotated to fix the positioning block in the ring groove so that the connecting head and the positioning ring are connected.

A nut is connected to the connecting rod. The nut is used to tighten the adjusting bolt, so that the reaction rod is fixed at the rated height.

The soil pressure device includes a pressure frame, a pressure grid and at least two jacks, the pressure grid is slidably arranged on one side of the pressure frame, and the jack is fixed on the other side of the pressure frame. side, and the jack is pressed against the reaction frame.

The pressurizing frame includes four pressurizing rods arranged in the shape of a square, two parallel slide grooves are arranged on at least two parallelly arranged pressurizing rods among the four pressurizing rods, and the pressurizing grid includes A plurality of strip-shaped pressure rods are provided with buckles which are slidably connected with the chute. The length of the pressure rod and the pressure rod is set according to the size of the load box. When the pressure rod pressurizes the soil, the soil in the laterally extruded part can be further squeezed by the pressure rod; in the utility model The pressure rod can be cylindrical, rectangular or other shapes. The middle of the zigzag pressurized frame is used for the passage of the pile body.

An even number of jacks is arranged on the pressurizing frame, and the even number of jacks are arranged symmetrically on the two pressurizing rods.

The pile body pressurizing device includes a cap and at least one jack, the jack is fixed on the cap, and the jack is pressed against the reaction frame.

The jack is provided with a pressure gauge.

A settlement data display device is provided between the reaction force frame and the cap, and the settlement data display device includes a dial indicator, and the dial indicator is fixed on the reaction force frame, and the probe of the dial indicator Press on the platform.

The test method of pile end back grouting chamber load is characterized in that, described test method comprises the following steps:

(1) making pile body;

(2) Place the load box on the base, and fill the load box with soil. The depth of the soil is greater than 1/3 of the height of the load box and less than 2/3 of the height of the load box;

(3) Pour the slurry mixed with water and cement in a certain proportion into the soil, and set the prefabricated piles in the slurry;

(4) The load box is filled with soil;

(5) Install soil pressurization device, pile body pressurization device and reaction force device;

(6) The soil pressurizing device pressurizes the soil until the land reaches a certain load;

(7) The pile body pressurization device pressurizes the pile body until the slurry bubble is destroyed or the pile body sinks, and the stress and settlement of the pile body are recorded.

The manufacturing method of described pile body, comprises the steps:

①Make the pile forming mold:

Take one or more hollow round steel pipes whose length is longer than the pile body, and cut the round steel pipes into two semi-arc or three arc-shaped arc petals along the axis direction;

Buckle the arc petals into a round steel pipe, and fasten the two ends and the middle of the round steel pipe with ring screws;

Seal one end of the round steel pipe, and put a layer of cotton gauze inside the end, and the other end is the open end;

②Make the pile reinforcement structure: choose thin steel bars to make a steel cage that can be put into the round steel pipe;

③Concrete pouring: Place the round steel pipe vertically with the open end up; put the steel cage into the round steel pipe from the open end, and pour concrete from the open end of the round steel pipe;

④Store at room temperature for 28 to 30 days;

⑤ Loosen the buckle screw, remove the three arc flaps, and you can see the formed pile body.

The pile body is made close to the actual project, and the test results are relatively accurate.

Another production method of the pile body: prepare one or more steel bars, apply cement mortar on the surface of the steel bars, and wait for the cement mortar to harden at room temperature to become a pile body. The size and load capacity of steel bars can be adjusted according to the conditions of soil and slurry bubbles. This test device is used to test the bearing mechanism of the soil between piles and the slurry bubble at the pile tip. The pile body must not be damaged during design. In actual engineering, because the strength of the pile body can be controlled, the foundation soil is usually damaged, and the pile body is not damaged. destroy. Therefore, you can also choose this method to make piles during simple tests.

In the step (3), water and cement are mixed according to the weight of 1:0.5-0.65, and then poured into the soil body to solidify to form slurry bubbles.

The diameter of the slurry bubble is two to three times the diameter of the pile body, and the depth of the slurry bubble is two to three times the diameter of the pile body. The diameter of the slurry bubble of cohesive soil is twice the diameter of the pile body, and the depth of the slurry bubble is twice the diameter of the pile body; the diameter of the slurry bubble of sandy soil is three times the diameter of the pile body, and the depth of the slurry bubble is the diameter of the pile body three times. At the same time, the grout climbs to a certain height along the axial direction of the pile body, which is 4-7 times the diameter of the pile body.

After the step (4) is completed, it needs to be placed at room temperature for 28 to 35 days. Ensure that the formed pulp bubbles meet the appropriate hardness requirements for actual engineering.

When the soil mass pressurizing device pressurizes the soil mass, the jack simultaneously pressurizes the pressurizing frame. This setting ensures that the soil is evenly compressed.

The beneficial effects of the pile end post grouting indoor load test device are:

(1) The grid spacing can be adjusted, the height of the reaction frame can be adjusted, the pressure of the land can be adjusted, and the grouting can be adjusted. Therefore, the device can simulate single piles, group piles, different pile lengths, different pile spacing, different Research on the properties of the pile after grouting under the soil layer, the test has a wide range of application;

(2) The soil weight can be detected and reflected by the pressure gauge on the jack and the volume of the load box, and the pressure bearing capacity of the pile body can be directly displayed by the pressure gauge and dial indicator, so the test of the device is intuitive and clear;

(3) The height of the reaction force frame can be adjusted according to the height of the soil body and/or the pile body, so the load test device in the post grouting chamber of the pile end is easy to install and operate, and the detection is labor-saving.

The beneficial effect of the test method of the post grouting indoor load of the pile end is:

(1) This test method can convert the piles and soils in the actual project in proportion to carry out the load test, thus ensuring the stability and firmness of the actual building;

(2) Use the post-grouting indoor load test device at the pile tip in the utility model to test. This test method can be tested indoors. The test is convenient and labor-saving, and the test position can be placed arbitrarily, and the application range is wide.

Description of drawings

Fig. 1 is the plan view of the test device of the present utility model.

FIG. 2 is a schematic cross-sectional structure diagram at A-A of FIG. 1 .

FIG. 3 is a schematic cross-sectional structure diagram at B-B of FIG. 1 .

Fig. 4 is a schematic cross-sectional view of the adjustment structure of the present invention.

Fig. 5 is a schematic diagram of another structural connector of the present invention.

Fig. 6 is a schematic diagram of a positioning ring matched with Fig. 5 .

In the figure, the load box 1, the reaction device 2, the chassis 201, the connecting rod 202, the reaction frame 203, the adjustment structure 204, the connection head 20a, the connection part 20c, the counterbore 20d, the clamping part 20e, the positioning head 20b, Sleeve 20f, retaining shoulder 20g, positioning ring 20h, positioning block 20i, guide groove 20j, ring groove 20k, reaction force rod 205, through hole 206, adjusting bolt 207, internal threaded hole 208, external thread 209, nut 210, soil Body pressure device 3, pressure frame 301, pressure rod 302, chute 303 pressure grid 304, pressure rod 305, buckle 306, pile body pressure device 4, cap 401, jack 5, pressure gauge 6 , dial indicator 7, soil body 8, slurry bubble 9, pile body 10.

Detailed ways

Further illustrate the utility model below in conjunction with accompanying drawing.

Embodiment one:

Referring to Fig. 1 to Fig. 4, the load test device in the post-grouting chamber of the pile end includes a load box 1, a reaction force device 2, a soil pressure device 3, and a pile body pressure device 4.

The counter force device 2 in the utility model includes a chassis 201 , four connecting rods 202 , a counter force frame 203 and an adjustment structure 204 . The reaction force frame 203 includes two reaction force rods 205 arranged in a cross shape and fixed in the middle. The reaction force rods 205 have two parallel upper and lower planes, and two ends of each reaction force rod 205 are respectively provided with a through The through holes 206 on the upper and lower planes. The lower ends of the four connecting rods 202 are provided with external threads 209, and are fixedly connected to the chassis 201 by nuts 210; the upper ends of the four connecting rods 202 are connected with the reaction force frame 203 through the adjustment structure 204, and the adjustment structure 204 can adjust the reaction force frame 203 on the height of the connecting rod 202. The adjustment structure 204 includes an adjustment bolt 207 that is penetrated in the through hole 206 and is rotatably connected with the reaction rod 205. The adjustment bolt 207 includes a connection head 20a and a positioning head 20b, and the positioning head 20b is detachably connected to the connection. Inside the head 20a; the connecting head 20a has a ring-shaped connecting portion 20c and a holding portion 20e, the internal thread hole 208 is opened on a pass of the connecting portion 20c and the holding portion 20e, and the holding portion 20e is located One end of the connecting portion 20c protrudes radially outward, and the other end of the connecting portion 20c is provided with a counterbore 20d; the positioning head 20b includes a sleeve 20f having a through hole 206 and a sleeve 20f The shoulder 20g at one end, the outer circumferential surface of the sleeve 20f is provided with an external thread 209, and the hole wall of the counterbore 20d is provided with an internal thread that matches the external thread 209 of the sleeve 20f. The diameter of the through hole of the barrel 20f is larger than the bottom diameter of the internal threaded hole 208 of the connecting portion 20c, that is, the connecting head 20a is connected to the upper end of the connecting rod 202, and the positioning head 20b is detachably connected to the connecting head 20a.

An external thread 209 is provided at the upper end of the connecting rod 202, and the external thread 209 at the upper end of the connecting rod 202 cooperates with the internal threaded hole 208 of the adjusting bolt 207; Prevent the adjustment bolt 207 from slipping out of the reaction force rod 205, while the clamping portion 20e and the shoulder 20g are provided with a clamping structure for convenient tools to screw the adjustment bolt 207, and a reference line for fine-tuning. A circle of the through hole 206 is provided with a scale line, and the reference line is compared with the scale line to make the fine-tuning result more intuitive and clear. Clamping structure such as hexagonal structure, card slot structure, etc.

The connecting rod 202 is connected with a nut 210 for adjusting the adjusting bolt 207 so that the adjusting bolt 207 is fixed at the rated height of the connecting rod 202, that is, the reaction force frame 203 is fixed at the rated height.

The load box 1 is arranged on the chassis 201, and the soil pressurizing device 3 and the pile pressurizing device 4 are both arranged between the load box 1 and the reaction force frame 203, and press against the reaction force frame 203 respectively superior. The load box 1 is a cubic box with an upper end opening, and a height mark is marked inside the load box 1; during the load test, the soil body 8 is filled in the load box 1, and the amount of the soil body 8 can be visually seen through the height mark; The pressure device 3 is used to adjust the pressure of the soil body 8 in the load box 1 to adjust the soil weight of the soil body 8; at least one pile body 10 is arranged in the soil body 8, and the pile body pressure device 4 applies pressure to measure The bearing capacity of a single pile body 10 or a plurality of pile bodies 10 .

The soil pressing device 3 includes a pressing frame 301 , a pressing grid 304 and two jacks 5 . The pressurizing frame 301 includes four pressurizing rods 302 arranged in a square shape, the middle of the square-shaped pressurizing frame 301 is used for the passage of the pile body 10, and two of the four pressurizing rods 302 are parallelly arranged. There are two parallel chutes 303 respectively; the pressure grid 304 includes several strip-shaped pressure rods 305, the length of the pressure rods 305 is set according to the size of the load box 1, and can be placed in the load box 1, A buckle 306 is provided on the pressure rod 305 , and the buckle 306 is slidably connected with the chute 303 ; For the convenience of installation, the square-shaped pressurizing frame 301 can be designed to be directly sleeved on the connecting rod 202, and is slidably connected with the connecting rod 202, that is, four corners of the square-shaped pressurizing frame are provided to connect with the connecting rod. 202 fit through holes.

The pile body pressurizing device 4 includes a platform 401 and a jack 5 . The cap 401 is pressed against the pile body 10, and the jack 5 is fixed on the cap 401; when there is only one pile body 10, the jack 5 directly presses the pile body 10; when there are multiple pile bodies 10, the jack 5 5 is located between multiple pile bodies 10 and pressurizes multiple pile bodies 10 at the same time; the jack 5 presses on the reaction force frame 203, and the pile body 10 is pressed by the reaction of the reaction force frame 203.

A pressure gauge 6 is provided on the jack 5 of the soil body pressurizing device 3 and the pile body pressurizing device 4, which is used to detect the force when the soil body pressurizing device 3 pressurizes the land, and is used to detect the pile body pressurizing device 4. The power to pressurize the pile body 10.

A settlement data display device is also provided between the reaction force frame 203 and the bearing platform 401. The settlement data display device includes a dial indicator 7, and the upper end of the dial indicator 7 is fixed on the reaction force frame 203 through a fixing seat. The probe at the lower end of the sub-meter 7 presses against the platform 401. In the initial state, the probe of the dial gauge 7 is under pressure, and the dial gauge 7 has an initial value. When the pile body 10 is moved down under pressure, the dial gauge 7 will display a current value. At this time, the difference between the initial value and the current value That is, the settlement of the pile body 10 .

The working principle of the load test device in the pile end post-grouting chamber is: first pressurize the soil body pressurization device 3 to a certain pressure and then stop pressurization; then pressurize the pile body pressurization device 4, and the pile body pressurization device 4 passes The reaction force frame 203 transmits the force to the cap 401 and to the pile body 10 until the slurry bubble 9 is destroyed or the soil body 8 settles. Observe the numerical changes of the pressure gauge 6 and the dial indicator 7 while pressurizing, and record each time Pressurized settlement deformation results and pressurized loads. During the test, the stress in the soil 8 is changed by the pressure of the soil pressurizing device 3 to change the depth of the soil 8, so as to change the length of the pile body 10; The size of the pile diameter, the distance between the pile body 10 and the number of the pile body 10; by designing the size of the slurry bubble 9 at the bottom of the pile body 10 according to the design requirements, to imitate the performance of the pile end reaming part of the cast-in-place pile in normal construction ; The soil body 8 placed in the load box 1 can be adjusted as cohesionless soil, cohesive soil or saturated soil body as required. Therefore, by this device, the research on the size and shape of the pile body 10 bearing capacity after pile tip grouting can be tested, including the study of single pile, pile group, different pile diameters, different pile lengths, pile tip grouting bubbles 9 sizes, different Simulation research on pile tip grouting and soil layers with different depths under the bearing layer has a wide range of applications and is convenient for testing.

The following steps are included in the test of the pile end post-grouting indoor load test device:

The first step is to make the pile body 10 .

Make the pile body 10 forming mold first: take one or more hollow round steel pipes whose length is longer than the pile body 10, cut the round steel pipes into two semi-arc or three arc-shaped arc petals along the axis direction; buckle the arc petals into A round steel pipe, and the two ends and the middle of the round steel pipe are fastened by ring screws; one end of the round steel pipe is sealed, and a layer of cotton gauze is placed inside the end, and the other end is an open end. Make the pile body 10 reinforcement structure: select the thin steel bar to make it into a reinforcement cage that can be put into the round steel pipe; place the round steel pipe vertically with the open end up; put the reinforcement cage into the round steel pipe from the open end, The open end of the steel pipe is poured into concrete. Place the round steel pipe filled with concrete for 28 to 30 days at normal temperature, actually 28 days. After the concrete is hardened, loosen the buckle screw, take off the three arc flaps, and you can see the formed pile body 10 . In order to make the setting of the cap 401 relatively stable during the test and to balance the stress on the pile body 10, the end surface of the pile body 10 exposed to the soil is usually made into a plane.

Another manufacturing method of the pile body 10: prepare one or more steel bars, apply cement mortar on the surface of the steel bars, and wait for the cement mortar to harden under normal temperature to form a pile body. The size and load capacity of steel bars can be adjusted according to the conditions of soil and slurry bubbles. This test device is to measure the load-bearing mechanism of the soil 8 between the piles and the slurry bubble at the pile end, and the pile body 10 is required not to be damaged during design; in actual engineering, because the strength of the pile body can be controlled, the foundation soil 8 is usually damaged, and the pile Body 10 is not destroyed. Therefore, this method can also be selected to make the pile body 10 during a simple test.

In the second step, the load box 1 is placed on the base, and the soil body 8 is filled in the load box 1. The depth of the soil body 8 is greater than 1/3 of the height of the load box 1 and less than 2/3 of the height of the load box 1; this embodiment will The soil body 8 is filled to 1/2 load box 1 height.

In the third step, as a preferred solution, water and cement are poured into the soil body 8 after water and cement are evenly mixed in a weight of 1:0.6, and the prefabricated pile body 10 is vertically arranged in the slurry; mixed by water and cement The slurry is poured into the soil and solidified to form a slurry bubble 9, and the prefabricated pile body 10 is arranged in the slurry bubble 9; in the present embodiment, three slurry bubbles 9 positions are set, and each slurry bubble 9 position is vertically arranged A pile body 10; the diameter of slurry bubble 9 is two to three times of pile body 10 diameters, and the depth of described slurry bubble 9 is two to three times of pile body diameter, and the slurry bubble diameter of cohesive soil is pile body 10 times. twice the diameter of the pile body, the depth of the slurry bubble is twice the diameter of the pile body; the diameter of the slurry bubble of the sandy soil is three times the diameter of the pile body, and the depth of the slurry bubble is three times the diameter of the pile body. At the same time, the grout climbs to a certain height along the axial direction of the pile body, which is 2-7 times the diameter of the pile body. The water and cement used to make the slurry bubble can be mixed by weight of 1:0.5, or by weight of 1:0.65.

The fourth step is to continue to fill the load box 1 with the soil body 8 until the entire load box 1 is filled. After this step, it needs to be placed at room temperature for 28 days, and the slurry bubble 9 is hardened before testing.

The fifth step is to install the soil pressurizing device 3, and set the pressure rods 305 according to the distribution of the pile body 10. The pressure rods 305 are densely distributed at the pile body 10, and the pressure rods 305 are placed in the load box 1, and the jack 5 Symmetrically arranged on two parallel pressure rods 302 ; at this time, the pile body 10 rises from the middle of the four pressure rods 302 , and the height of the pile body 10 is higher than the pressure rods 302 . The pile body pressurizing device 4 is installed so that the cap 401 is directly pressed against the pile body 10, and the jack 5 is pressed against the pile body 10 in the middle. Install the reaction force device 2, set the positioning head 20b, the reaction force frame 203, and the connecting head 20a on the connecting rod 202 from bottom to top in sequence. It can be moved upward arbitrarily, but the connecting head 20a needs to be rotated and screwed to the connecting rod 202. When the connecting head 20a is screwed to a suitable height, the four positioning heads 20b are screwed to the connecting head 20a from bottom to top, so that the reaction force frame 203 is positioned at a suitable height; at this time, the reaction force frame 203 is in contact with the jack 5, and the dial indicator 7 is connected between the reaction force frame 203 and the platform 401; if the height of the reaction force frame 203 needs to be adjusted, the positioning The adjustment is performed after the head 20b is released.

In the sixth step, the soil body pressurizing device 3 pressurizes the soil body 8, the jack 5 acts on the reaction force frame 203, and the reaction force is given to the two pressure rods 302 of the pressure frame 301 and the pressure rods of the pressure grid 304 305 exerts force on the soil body 8 until the land reaches a certain load. A certain load refers to the density of the soil used for simulation in the experiment, that is, the density of the soil in the actual project, which is measured by the ring knife method. By this test method, the thickness of the soil body can be obtained, which can be calculated by the formula h=q/r specifically, where h is the thickness of the soil body, q is the pressure applied by the soil body pressurizing device 3 to the soil body, and r is Soil weight. The soil weight is obtained by multiplying the density of the soil by ring knife detection by 9.8. For example, if a pressure of 100kpa is applied to the soil, after filling the soil, measure the density of the soil with a ring knife, and multiply it by 9.8 to calculate the weight of the soil is 20kN/m3, so that it can be calculated by the above formula under the pressure of 100kpa, The piles and slurry bubbles are set in the soil at a depth of 5 meters.

In the seventh step, the pile body pressurizing device 4 pressurizes the pile body 10 until the slurry bubble 9 is destroyed or the soil body 8 descends, and the stress and settlement of the pile body 10 are recorded. Excavate the damaged slurry bubbles and conduct scanning electron microscope analysis; at the same time, prepare slurry bubbles in the laboratory with the same water-cement ratio, but this slurry bubble has not been compressed, and placed in the same time as the pile end slurry bubble The uniaxial compressive strength test is carried out on the universal machine, and the difference between the destroyed pulp bubble and the pulp bubble directly tested on the universal machine is analyzed, and then applied to the actual project.

It can be seen that the utility model can study whether the pulp bubble damage or the soil damage under different pulp bubble sizes and different pulp bubble moduli. Grouting should be used with caution in layers, because the purpose of improving bearing capacity and reducing settlement has not been achieved, and the test results can guide the application of actual engineering. The modulus of the slurry bubble is the compressive modulus of the soil, that is, the ratio of the vertical stress increment to the corresponding strain of the slurry bubble under the condition of complete confinement.

Embodiment two:

5 and 6, the difference between this embodiment and the first embodiment is that the adjusting bolt 207 includes a connecting head 20a and a positioning ring 20h, and the connecting head 20a has an annular connecting portion 20c and a clamping portion 20e, so The internal threaded hole 208 runs through the connecting portion 20c and the clamping portion 20e; the clamping portion 20e is located at one end of the connecting portion 20c and protrudes radially outward, and the positioning ring 20h is clamped at the other end of the connecting portion 20c . Specifically: the outer surface of the annular connecting portion 20c is provided with two guide grooves 20j along the axial direction and two annular grooves 20k extending along the same circumferential direction of the connecting portion 20c, one guide groove 20j communicates with one annular groove 20k The inside of the positioning ring 20h has two positioning blocks 20i protruding inward. When the positioning ring is sleeved on the connecting part 20c, the two positioning blocks 20i can be set in the guide groove 20j at the same time, and then the positioning ring is rotated to fix the positioning blocks 20i on the ring. The connecting head 20a and the positioning ring 20h form a connection in the groove 20k.

The content described in the embodiments of this specification is only an enumeration of the realization forms of the utility model concept, and the protection scope of the utility model should not be regarded as being limited to the specific forms stated in the embodiments, and the protection scope of the utility model also includes Equivalent technical means that those skilled in the art can think of according to the concept of the utility model.

Claims (10)

1. A load test device in the back grouting chamber of a pile end, is characterized in that: comprise load box, reaction force device, soil mass pressurization device, pile body pressurization device; Described reaction force device comprises chassis, some connecting rods and Reaction frame; the lower ends of the plurality of connecting rods are fixedly connected to the chassis, the upper ends of the plurality of connecting rods are connected with the reaction frame, and there is an adjustable height adjustment mechanism between the connecting rods and the reaction frame. Structure; the load box is arranged on the chassis, and the soil pressurization device and the pile body pressurization device are both arranged between the load box and the reaction frame and press against the reaction frame respectively. 2. The indoor load test device for post-grouting at a pile end as claimed in claim 1, wherein the reaction frame comprises two reaction rods fixedly connected in a cross shape, and the two reaction rods are The ends are respectively provided with through holes. 3. A load test device for post grouting at pile ends as claimed in claim 2, characterized in that: the adjustment structure includes an adjustment bolt that is penetrated in the through hole and is rotatably connected with the reaction bar, and the The adjusting bolt is provided with an internal thread hole, and the upper end of the connecting rod is provided with an external thread, and the external thread at the upper end of the connecting rod cooperates with the internal thread hole of the adjusting bolt. 4. a kind of post-grouting chamber load test device of pile end as claimed in claim 3 is characterized in that: described adjusting bolt comprises connecting head and locating head, and described locating head is detachably connected in the connecting head; The connecting head has an annular connecting part and a clamping part, the clamping part is located at one end of the connecting part and protrudes radially outward, and the other end of the connecting part is provided with a counterbore; the described The positioning head includes a sleeve with a through hole and a shoulder at one end of the sleeve, an external thread is provided on the outer circumference of the sleeve, and the wall of the counterbore hole is provided with an external thread that matches the sleeve. The diameter of the through hole of the sleeve is larger than the bottom diameter of the inner threaded hole. 5. a kind of post-pile grouting chamber load test device as claimed in claim 3, it is characterized in that: described adjustment bolt comprises connector and positioning ring, and connector has ring-shaped connection part and clamping part, so The clamping part is located at one end of the connecting part and protrudes radially outward, and the positioning ring is clamped at the other end of the connecting part. 6. A load test device for pile end post-grouting chamber according to any one of claims 1 to 5, characterized in that: the soil pressurization device comprises a pressurization frame, a pressurization grid and at least two A jack, the pressurization grid is slidably arranged on one side of the pressurization frame, the jack is fixed on the other side of the pressurization frame, and the jack is pressed against the reaction force frame. 7. A load test device for post-grouting pile ends as claimed in claim 6, characterized in that: said pressurizing frame comprises four four pressurizing rods arranged in the shape of a square, and the four pressurizing rods There are two parallel chutes on at least two pressure rods arranged in parallel, and the pressure grid includes several elongated pressure rods, and the pressure rods are provided with clips that are slidably connected to the chute. buckle; an even number of jacks is arranged on the pressurizing frame, and the even number of jacks are arranged symmetrically on the two pressurizing rods. 8. The post-grouting indoor load test device for pile ends according to any one of claims 1 to 5, wherein the pile pressurizing device includes a cap and at least one jack, and the jack is fixed On the bearing platform, and the jack is pressed on the reaction frame. 9 . The indoor load test device for post grouting at the pile end as claimed in claim 8 , wherein the jack is provided with a pressure gauge. 10 . 10. A load test device for post grouting at pile ends as claimed in claim 8, characterized in that: a settlement data display device is provided between the reaction force frame and the cap, and the settlement data display device includes a A dial gauge, the dial gauge is fixed on the reaction frame, and the probe of the dial gauge presses against the platform.

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