CN204738324U - Clump of piles basis single pile vertical bearing capacity detecting system - Google Patents

Abstract

The utility model discloses a detection system for the vertical bearing capacity of a single pile of a pile group foundation. The utility model is mainly composed of a test pile, a reaction force anchor system and a test detection system; The pile is composed of engineering piles and caps around the pile; the test detection system is composed of a loading system, a deformation monitoring system and an automatic control system; the hydraulic loading device of the loading system is installed on the top of the test section of the test pile; the deformation monitoring instrument of the deformation monitoring system is installed The side of the table is above the ground; the deformation monitoring instrument and the bearing test section are rigidly connected by rigid rods. The utility model ingeniously borrows the foundation of the engineering pile cap as the reaction force anchoring system. Using the utility model to test the bearing capacity of the pile foundation is low in cost and does not need to adjust the specifications of the original engineering pile. The test result is intuitive and reliable. The loading equipment can be reused, and the test pile can be used Continue to use as engineering pile.

Description

A testing system for the vertical bearing capacity of a single pile in a pile group foundation

technical field

The utility model relates to the field of engineering, in particular to a detection system for the vertical bearing capacity of a single pile of a pile group foundation.

Background technique

Most bridge pile foundations use rigid caps of group pile foundations as the supporting structure for the bearing capacity of the upper structure of the bridge pier. Change measurement method.

The disadvantages of the stacking method are that the required static load counterweight is large, the amount is large, the counterweight platform and the bracket are heavy, and the workload of transportation, installation and dismantling is huge, the labor intensity of the testing personnel is extremely high, the safety is poor, the testing time is long, and the testing cost is very high. It is very high; and it is often impossible to carry out normal detection due to the limitations of transportation, site and natural conditions.

In the anchor pile method, most of the anchor piles used are four and are pulled simultaneously. The value of the load test depends on the pull-out capacity of the four anchor piles and the weight of the stacked load on the reaction frame. When the static load test specification is obviously larger than the anchor pile It is impossible to carry out the test according to the above method when the pile pull-out capacity and piled load capacity; therefore, the original engineering pile is often used as the anchor pile after the specification is increased, which increases the cost and time of the pile foundation bearing capacity test, And the damage of the anchor pile will be more serious.

The disadvantage of the self-balancing method is that the maximum load is the negative friction resistance of the pile side in the upper soil layer of the load box, while the actual pile bearing capacity is the sum of the positive friction resistance of the pile side and the pile end resistance, resulting in a deviation between the converted foundation pile bearing capacity and the test value , and the accurate selection of the balance point position is also difficult to control, which often leads to the main reason for the failure of the test. At the same time, the test loading device is located in the middle and lower part of the foundation pile, and it cannot be recycled and reused after the test is completed.

The disadvantages of the high-strain dynamic testing method are that the theoretical principles and the limitations of the field test parameters cause deviations in the results; the hammer force of the pile head is not easy to control, and once the force is too large, the pile structure will be damaged, and it is not suitable for super-long pile load tests.

Utility model content

The purpose of the utility model is to provide a vertical bearing capacity detection system of a pile group foundation single pile, which is used for testing the bearing capacity of the foundation piles of the bridge pile group foundation. The system overcomes the deficiencies of existing pile foundation vertical bearing capacity detection methods, and the pile foundation detection results are close to the real situation. It has the following characteristics: (1) static load method is used; (2) pile top is loaded vertically; (3) ) The reaction device is simple and practical, (4) The loading device can be recycled and reused; (5) The test operation is simple and the applicability is strong.

The purpose of this utility model is achieved through the following technical solutions:

A detection system for the vertical bearing capacity of a single pile of a pile group foundation, mainly composed of a test pile 1, a reaction force anchoring system 2, and a test detection system 3.

The test pile 1 is the foundation pile at the center of the foundation of the pile cap 22, and is composed of two parts, the load-bearing test section 1a and the post-cast lap joint section 1b. The load-bearing test section 1a is composed of a steel cage 12a and concrete 11a, and the top of the load-bearing test section 1a is embedded with a pressure-bearing steel plate 13, which is used for the connection and anchorage of the test pile 1 and the bottom of the cap 22. Post-casting lap section 1b is composed of lapping steel cage 12b and post-casting concrete 11b. Both ends of the overlapping reinforcement cage 12b are respectively welded to the pressure-bearing anchor steel plate 23 at the bottom of the bearing platform 22 and the pressure-bearing steel plate 13 at the top of the load-bearing test section 1a of the test pile 1 . The post-cast lap section 1b will be constructed after the bearing capacity test is completed.

In the test pile 1, the lap steel cage 12b of the post-cast lap section 1b can be replaced by a steel tube, and the steel tube is used not only as a load-bearing structure, but also as a concrete pouring formwork structure. The steel casing 14 at the top of the load-bearing test section 1a of the test pile 1 (the steel casing needs to be embedded in the pile head during the construction of the bored impact pile to prevent the hole from collapsing) is not removed, and forms a steel tube concrete with the pressure steel plate 13 and concrete 11a Structure, improve the pile end compression and crack resistance.

The reaction force anchoring system 2 is composed of engineering piles 21 around the foundation pile and a cap 22 on the top of the pile. The engineering pile 21 used for anchoring is anchored in the top cap 22 through the steel cage of the pile body. A pressure-bearing anchoring steel plate 23 is pre-embedded in the center of the bottom surface of the cap 22 for connecting and anchoring the test pile 1 and the cap 22 . The pressure-bearing anchoring steel plate 23 is anchored in the platform 22 through the anchoring steel bar 24 .

The test detection system 3 is composed of a loading system 33 , a deformation monitoring system 32 and an automatic control system 31 . The test detection system 3 is dismantled after the bearing capacity test is completed.

The loading system 33 includes an oil storage tank 33c, an oil delivery pipeline 33b, an oil pressure gauge 33d and a hydraulic loading device 33a. The hydraulic loading device 33a is a jack, which is installed on the top of the test section 1a of the test pile 1, and a single jack or multiple jacks are selected according to the test load and working conditions.

The deformation monitoring system 32 includes a deformation monitoring instrument 32a and a rigid rod 32b, and the deformation monitoring instrument 32a is a device such as a dial indicator or a dial indicator. The deformation monitoring instrument 32a is installed above the ground on the side of the platform 22 for convenient observation. The deformation monitoring instrument 32a is rigidly connected to the load-bearing test section 1a of the test pile 1 through a rigid rod 32b. Since the deformation of the load-bearing test section 1a of the test pile 1 is synchronized with the deformation of the rigid rod 32b, the deformation of the pile is realized by measuring the deformation of the rigid rod 32b. monitor.

The automatic control system 31 is composed of a control system 31a and a sensor 31b. The control system 31a is connected to the loading system 33 and the deformation monitoring system 32 through the sensor 31b to control them.

The steps of the method for testing the bearing capacity of the pile foundation using the above detection system are as follows:

Step 1: According to the test requirements, select a suitable pile group foundation. The bottom of the pile cap 22 is required to be placed on the ground, the foundation of the pile group cap 22 is biaxially symmetrical, and the cap 22 meets the rigid angle requirements.

Step 2: Construct the pile cap 22 according to the conventional method, select the foundation pile at the center of the cap 22 as the test pile 1, and require a certain distance between the top of the test pile 1 bearing the test section 1a and the bottom of the cap 22, which satisfies the installation of the hydraulic loading device 33a space.

Step 3: Pre-embed the pressure-bearing steel plate 13 and the pre-embed pressure-bearing anchor steel plate 23 at the corresponding positions between the top of the test pile 1 bearing the test section 1a and the bottom of the bearing platform 22 .

Step 4: Excavate the test operation channel 4 at the bottom of the cap 22, which requires little disturbance to the pile group foundation and meets the requirements for manual operation and test device layout space.

Step 5: Install a vertical hydraulic loading device 33a on the top of the bearing test section 1a of the test pile 1, and install an oil storage tank 33c matching the hydraulic loading device 33a, an oil pipeline 33b, and an oil pressure gauge 33d; install a deformation monitoring instrument on the side of the cap 22 32a, the deformation monitoring instrument 32a is rigidly connected with the test section 1a of the test pile 1 through the rigid rod 32b. The automatic control system 31 is then installed.

Step 6: Carry out graded loading according to the established test plan, and complete the loading test.

Step 7: Dismantle the test detection system 3, and carry out the construction of the lap joint section 1b of the test pile. Weld the two ends of the overlapping reinforcement cage 12b to the pressure-bearing anchor steel plate 23 at the bottom of the platform 22 and the pressure-bearing steel plate 13 at the top of the test section 1a of the test pile 1, install the template 5 for the overlapping section, and pour concrete 11b to complete the pile head connection.

Step 8: After the test, backfill the operation channel 4 at the bottom of the cap 22, protect the cap 22, and complete the test.

Compared with the existing technology, considering that the bridge pile foundation in the railway industry mostly adopts the rigid pile cap of the pile group foundation as the superstructure support structure, the utility model skillfully borrows the foundation of the pile group pile foundation as the reaction force anchoring system, and provides a detection system to test the pile foundation Bearing capacity, without adjusting the original engineering pile specifications, the test results are intuitive and reliable, the loading equipment can be reused, the test pile can continue to be used as an engineering pile, the test cost is low, and the economic benefit is good.

Description of drawings

Fig. 1 is the utility model test schematic diagram;

Fig. 2 is a schematic diagram of installation of the utility model test detection system;

Fig. 3 is the schematic diagram of the utility model test pile connecting pile;

Fig. 4 is the assembling drawing of test pile connecting pile of the present utility model;

Fig. 5 is a schematic diagram of the plane layout of pile group foundations of the present invention;

In the figure, 1-test pile, 1a-bearing test section, 11a-concrete, 12a-reinforcing cage, 13-bearing steel plate, 14-steel casing, 1b-post-cast lap section, 11b-post-cast concrete, 12b - lap reinforcement cage, 5- lap section template; 2- reaction force anchoring system, 21- engineering pile, 22- cap, 23- pressure anchoring steel plate, 24- anchoring steel bar; 3- test detection system, 31- Automatic control system, 31a-control system, 31b-sensing instrument, 32-deformation monitoring system, 32a-deformation monitoring instrument, 32b-rigid rod, 33-loading system, 33a-hydraulic loading device, 33b-oil pipeline, 33c- Oil storage tank, 33d-oil pressure gauge, 4-operation channel.

Detailed ways

The utility model will be further described in detail below in conjunction with the embodiments and accompanying drawings. These descriptions are convenient for a clear understanding of the utility model, but they do not limit the utility model.

Example 1

A system for detecting the vertical bearing capacity of a single pile in a pile group foundation, the schematic diagrams of which are shown in Fig.

The test pile 1 is the foundation pile at the center of the foundation of the pile cap 22, and is composed of two parts, the load-bearing test section 1a and the post-cast lap joint section 1b. The load-bearing test section 1a is composed of a steel cage 12a and concrete 11a, and the top of the load-bearing test section 1a is embedded with a pressure-bearing steel plate 13, which is used for the connection and anchorage of the test pile 1 and the bottom of the cap 22. Post-casting lap section 1b is composed of lapping steel cage 12b and post-casting concrete 11b. Both ends of the overlapping reinforcement cage 12b are respectively welded to the pressure-bearing anchor steel plate 23 at the bottom of the bearing platform 22 and the pressure-bearing steel plate 13 at the top of the load-bearing test section 1a of the test pile 1 . The post-cast lap section 1b will be constructed after the bearing capacity test is completed.

In the test pile 1, the lap steel cage 12b of the post-cast lap section 1b can be replaced by a steel tube, and the steel tube is used not only as a load-bearing structure, but also as a concrete pouring formwork structure. The steel casing 14 at the top of the load-bearing test section 1a of the test pile 1 (the steel casing 14 needs to be embedded at the pile head during the construction of the bored impact pile to prevent the hole from collapsing) is not removed, and forms a steel pipe with the pressure-bearing steel plate 13 and concrete 11a Concrete structure, improve the pile end compression and crack resistance.

The reaction force anchoring system 2 is composed of engineering piles 21 around the foundation pile and a cap 22 on the top of the pile. The engineering pile 21 used for anchoring is anchored in the top cap 22 through the steel cage of the pile body. A pressure-bearing anchoring steel plate 23 is pre-embedded in the center of the bottom surface of the cap 22 for connecting and anchoring the test pile 1 and the cap 22 . The pressure-bearing anchoring steel plate 23 is anchored in the platform 22 through the anchoring steel bar 24 .

The test detection system 3 is composed of a loading system 33 , a deformation monitoring system 32 and an automatic control system 31 . The test detection system 3 is dismantled after the bearing capacity test is completed.

The loading system 33 includes an oil storage tank 33c, an oil delivery pipeline 33b, an oil pressure gauge 33d and a hydraulic loading device 33a. The hydraulic loading device 33a is a jack, which is installed on the top of the test section 1a of the test pile 1, and a single jack or multiple jacks are selected according to the test load and working conditions.

The deformation monitoring system 32 includes a deformation monitoring instrument 32a and a rigid rod 32b, and the deformation monitoring instrument 32a is a device such as a dial indicator or a dial indicator. The deformation monitoring instrument 32a is installed above the ground on the side of the platform 22 for convenient observation. The deformation monitoring instrument 32a is rigidly connected to the load-bearing test section 1a of the test pile 1 through a rigid rod 32b. Since the deformation of the load-bearing test section 1a of the test pile 1 is synchronized with the deformation of the rigid rod 32b, the deformation of the pile is realized by measuring the deformation of the rigid rod 32b. monitor.

The automatic control system 31 is composed of a control system 31a and a sensor 31b. The control system 31a is connected to the loading system 33 and the deformation monitoring system 32 through the sensor 31b to control them.

The steps of the method for testing the bearing capacity of the pile foundation using the above detection system are as follows:

Step 1: According to the test requirements, select a suitable pile group foundation. It is required that the bottom of the pile cap 22 be placed on the ground.

Step 2: Construct the pile cap 22 according to the conventional method, select the foundation pile at the center of the cap 22 as the test pile 1, and require a certain distance between the top of the test pile 1 bearing the test section 1a and the bottom of the cap 22, which satisfies the installation of the hydraulic loading device 33a space.

Step 3: Pre-embed the pressure-bearing steel plate 13 and the pre-embed pressure-bearing anchor steel plate 23 at the corresponding positions between the top of the test pile 1 bearing the test section 1a and the bottom of the bearing platform 22 .

Step 4: Excavate the test operation channel 4 at the bottom of the cap 22, which requires little disturbance to the pile group foundation and meets the requirements for manual operation and test device layout space.

Step 5: Install a vertical hydraulic loading device 33a on the top of the bearing test section 1a of the test pile 1, and install an oil storage tank 33c, an oil pipeline 33b, and an oil pressure gauge 33d matched with the hydraulic loading device 33a; install a deformation monitoring instrument on the side of the cap 22 32a, the deformation monitoring instrument 32a is rigidly connected with the test section 1a of the test pile 1 through the rigid rod 32b. The automatic control system 31 is then installed.

Step 6: Carry out graded loading according to the established test plan, and complete the loading test.

Step 7: Dismantle the test detection system 3, and carry out the construction of the lap joint section 1b of the test pile. Weld the two ends of the overlapping reinforcement cage 12b to the pressure-bearing anchor steel plate 23 at the bottom of the platform 22 and the pressure-bearing steel plate 13 at the top of the test section 1a of the test pile 1, install the template 5 for the overlapping section, and pour concrete 11b to complete the pile head connection.

Step 8: After the test, backfill the operation channel 4 at the bottom of the cap 22, protect the cap 22, and complete the test.

The content not described in detail in this specification belongs to the prior art known to those skilled in the art.

Claims (6)

1. a multi-column pier foundation vertical bearing capacity of single pile detection system, is characterized in that: primarily of test pile (1), counter-force anchor system (2), testing inspection system (3) composition;

Test pile (1) is group pile cap (22) base center place foundation pile, and test pile (1) comprises bearing test section (1a); Bearing test section (1a) is made up of reinforcing cage (12a) and concrete (11a), the pre-buried pressure-bearing steel plate (13) in bearing test section (1a) top;

Counter-force anchor system (2) is made up of engineering pile around foundation pile (21) and cushion cap (22); Engineering pile (21) is anchored in top cushion cap (22) by pile body reinforcing cage; The pre-buried pressure-bearing anchor plate (23) of cushion cap (22) bottom center, pressure-bearing anchor plate (23) is anchored in cushion cap (22) by anchor bar (24);

Testing inspection system (3) is made up of loading system (33), DEFORMATION MONITORING SYSTEM (32) and automatic control system (31);

Loading system (33) comprises fuel reserve tank (33c), oil pipeline (33b), oil pressure gauge (33d) and hydraulic loading device (33a); Hydraulic loading device (33a) is arranged on test pile (1) bearing test section (1a) top;

DEFORMATION MONITORING SYSTEM (32) comprises deformation monitoring instrument (32a) and rigid rod (32b); Deformation monitoring instrument (32a) is arranged on more than cushion cap (22) ground, side; Be rigidly connected by rigid rod (32b) between deformation monitoring instrument (32a) and test pile (1) bearing test section (1a);

Automatic control system (31) is made up of control system (31a) and sensor apparatus (31b), and control system (31a) to be connected with loading system (33) and DEFORMATION MONITORING SYSTEM (32) by sensor (31b) and to control it.

2. multi-column pier foundation vertical bearing capacity of single pile detection system according to claim 1, it is characterized in that: after described test pile (1) also comprises, water lap segment (1b), after water lap segment (1b) by overlap joint reinforcing cage (12b) and rear pouring concrete (11b) form; Overlap joint reinforcing cage (12b) two ends are welded in cushion cap (22) end pressure-bearing anchor plate (23) and test pile (1) bearing test section (1a) top pressure-bearing steel plate (13) respectively.

3. multi-column pier foundation vertical bearing capacity of single pile detection system according to claim 2, is characterized in that: after water lap segment (1b) overlap joint reinforcing cage (12b) steel pipe cylinder replace.

4. multi-column pier foundation vertical bearing capacity of single pile detection system according to claim 1, is characterized in that: the embedding steel pile casting (14) in test pile (1) bearing test section (1a) top is not removed.

5. multi-column pier foundation vertical bearing capacity of single pile detection system according to claim 1, is characterized in that: described hydraulic loading device (33a) is jack.

6. multi-column pier foundation vertical bearing capacity of single pile detection system according to claim 1, is characterized in that: described deformation monitoring instrument (32a) is dial gauge or dial gage.