CN114687387B - Simulation entity controller platform of foundation pit axial force servo system - Google Patents
Simulation entity controller platform of foundation pit axial force servo system Download PDFInfo
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- CN114687387B CN114687387B CN202210125117.7A CN202210125117A CN114687387B CN 114687387 B CN114687387 B CN 114687387B CN 202210125117 A CN202210125117 A CN 202210125117A CN 114687387 B CN114687387 B CN 114687387B
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- 238000004088 simulation Methods 0.000 title claims abstract description 18
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 124
- 239000010959 steel Substances 0.000 claims abstract description 124
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 115
- 238000012360 testing method Methods 0.000 claims abstract description 44
- 238000002347 injection Methods 0.000 claims abstract description 26
- 239000007924 injection Substances 0.000 claims abstract description 26
- 238000005259 measurement Methods 0.000 claims abstract description 10
- 239000013307 optical fiber Substances 0.000 claims abstract description 9
- 229910000838 Al alloy Inorganic materials 0.000 claims description 18
- 239000007787 solid Substances 0.000 claims description 18
- 238000006073 displacement reaction Methods 0.000 claims description 16
- 230000002457 bidirectional effect Effects 0.000 claims description 13
- 239000004576 sand Substances 0.000 claims description 12
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- 239000011521 glass Substances 0.000 claims description 7
- 238000012545 processing Methods 0.000 claims description 5
- 238000010276 construction Methods 0.000 claims description 4
- 238000003860 storage Methods 0.000 claims description 4
- 238000003466 welding Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 abstract description 13
- 238000009412 basement excavation Methods 0.000 abstract description 5
- 238000011160 research Methods 0.000 abstract description 5
- 238000009826 distribution Methods 0.000 abstract description 2
- 229940099259 vaseline Drugs 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000003825 pressing Methods 0.000 description 4
- 229920005372 Plexiglas® Polymers 0.000 description 3
- 230000006835 compression Effects 0.000 description 3
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
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Classifications
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/02—Foundation pits
- E02D17/04—Bordering surfacing or stiffening the sides of foundation pits
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2300/00—Materials
- E02D2300/0026—Metals
- E02D2300/0029—Steel; Iron
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2300/00—Materials
- E02D2300/0026—Metals
- E02D2300/0035—Aluminium
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2600/00—Miscellaneous
- E02D2600/10—Miscellaneous comprising sensor means
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- General Engineering & Computer Science (AREA)
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Abstract
The invention discloses a foundation pit axial force servo system simulation entity controller platform, which adopts a water injection loading mode to carry out steel support axial force compensation simulation, namely, the water injection in a water bearing tank is carried out in a grading manner by utilizing pulleys in the process of eccentric loading and earth layering block excavation unloading of a foundation pit by controlling the flow rate and the flow speed of a water pump and an electromagnetic valve and a stable water head with constant water level of the water injection tank. In the invention, the deformation of the underground diaphragm wall steel plate is extended, the indirect measurement is carried out by using the dial indicator, and the optical fiber deformation monitor and the strain gauge are simultaneously used for large-scale distribution control on the underground diaphragm wall steel plate, so that the important parameters of foundation pit deformation control are obtained, and the general deformation process of the underground diaphragm wall is mastered, thereby facilitating data arrangement and analysis. The invention can be used as a research means of an indoor test, is used for analyzing the stress deformation characteristic of the underground diaphragm wall and researching the deformation control mechanism loading mode of the foundation pit axial force servo system, and is simple in field test and easy to operate.
Description
Technical Field
The invention belongs to the technical field of foundation pit engineering construction, relates to foundation pit deformation control test research, and relates to a foundation pit axial force servo system simulation entity controller platform, in particular to a steel support axial force servo system simulation entity controller platform for an oversized and ultra-deep foundation pit.
Background
As the urban process is continuously accelerated, large underground engineering projects are gradually increased, foundation pit engineering is continuously developed towards larger and deeper trends, and new challenges are also provided for the technical requirements of various foundation pit engineering. Construction quality of foundation pit earthwork excavation, steel support structure erection, deformation control and the like depends on the application and setting effects of steel support axial force to a great extent. At present, on the servo of the steel support axial force, one is to use the axial force of the steel support in the foundation pit supporting process as a measurement and control target to carry out servo, the axial force is caused by soil pressure, but the influence factors of the change rule of the soil pressure are complex and difficult to master accurately, the measurement and control system often cannot achieve an ideal control effect, and the other is to use the displacement of the steel support end in the foundation pit supporting process as a servo standard, and in the range allowed by the axial force, the deformation of the foundation pit is controlled in a grading manner through applying the axial force, and meanwhile, the axial force change rule of the common steel support is referred.
Under the condition that the application force and the setting mode of the steel support axial force are effective, the steel support axial force servo system has obvious control effect on foundation pit deformation. The foundation pit steel support axial force hydraulic servo system can effectively control foundation pit deformation and is widely popularized and applied, but at present, the intelligent research of the foundation pit axial force servo control system is still in a primary stage, and how to demonstrate the intelligent regulation and control mechanism of the foundation pit axial force servo control system more simply, intuitively and sensitively, so that the foundation pit deformation control effect is more dynamic, three-dimensional and visual, which is a direction worthy of research.
Disclosure of Invention
The invention aims to solve the defects of the existing foundation pit axial force servo system indoor test research scheme, and provides a foundation pit axial force servo system simulation entity controller platform integrating foundation pit earth excavation unloading, steel support structure erection, underground diaphragm wall deformation control, additional load application, axial force displacement monitoring and the like, so that the deformation control effect of the foundation pit under different servo setting modes is displayed in a three-dimensional dynamic mode by the same control platform.
The technical scheme adopted by the invention is as follows:
a foundation pit axial force servo system simulation entity controller platform comprises a test box, a load system, a measurement transmission system and a control output system; the test box is used for containing sand and placing the underground diaphragm wall to simulate foundation pit construction, and the underground diaphragm wall comprises underground diaphragm wall steel plates at two sides and steel supports arranged between the underground diaphragm wall steel plates; the load system can provide eccentric load of the foundation pit and axial force load of the steel support, and the measurement transmission system is used for detecting the applied axial force and displacement of the underground continuous wall steel plate; the control output system is used for processing the collected axial force value and displacement value and giving out a control signal to control the loading condition of the load system.
In the technical scheme, further, the force compensation simulation of the steel support shaft is carried out at one end or two ends of the steel support in a water injection loading mode; the steel support assembly is realized on the basis of a steel support assembly, the steel support assembly comprises an end spring sleeve and a solid steel rod, the end spring sleeve is formed by coaxially arranging three sections of aluminum alloy pipes with scales and built-in springs, two ends of a middle section are externally connected with two other sections so that the three sections of aluminum alloy pipes form a length-adjustable sleeve, a middle channel penetrates through the whole axis, and the solid steel rod is arranged at two ends in the middle channel and extends out of a test box through an underground continuous wall steel plate; the two ends of the solid steel rod are respectively connected with the spring dynamometer through tensile steel wires and then are connected with the water bearing tank by bypassing the pulley fixed outside the test box.
Further, the measuring and transmitting system comprises a tension-compression bidirectional force transducer, a through section is arranged on the underground continuous wall steel plate from bottom to top and is used for being filled with an upper fit section and a lower fit section, the upper fit section and the lower fit section are matched to be used for placing and fixing the tension-compression bidirectional force transducer, and an expansion end is arranged on the outer section of the solid steel rod close to two sides of the test box so as to limit and install a dial indicator.
Further, two ends of the steel support are provided with a pressurizing top cover, a small hole is formed in the middle shaft of the pressurizing top cover, the outer diameter of the top cover is slightly smaller than the inner diameter of the aluminum alloy sleeve, the diameter of the inner diameter of the top cover is slightly larger than that of the solid steel rod, one end of the hollow connecting piece is connected with a pulling and pressing bidirectional force transducer, and the other end of the hollow connecting piece is movably connected with the end part of the steel support.
Further, the outer wall of the lower fit strip of the lower fit section is welded with a support leg, the tail end of the support leg is provided with threads, the lower fit section can be embedded into the through section of the underground continuous wall steel plate until the reserved hole is formed, and the outer threads are tightly connected with the section expansion end connector of the pit outer steel support just through the reserved hole.
Furthermore, the upper engaging section is formed by mutually welding a top crosspiece and an upper engaging strip, the upper engaging section can be embedded into a through section of the underground continuous wall steel plate, and the upper engaging section is just jointed with the lower engaging section in the through section.
Further, the outer wall of the water bearing tank is marked with capacity scales, an inclined buffer guide plate is fixed in the water bearing tank, a water discharge valve is respectively arranged at the upper part and the lower part of the water bearing tank, the water bearing tank is connected with a water injection tank at the upper part, and the water storage tank is connected at the lower part of the water bearing tank; the water injection tank outer wall is along equidistant a plurality of solenoid valves of high distribution, can control the stable flood peak of water injection tank water level height constancy according to experimental demand, and each solenoid valve below all sets up a water drainage tank, the water drainage tank is equipped with one row of water conservancy diversion mouth, and the overflow water of water injection tank can be collected and discharged to the water drainage tank.
Further, the measuring and transmitting system comprises an optical fiber deformation monitor and a strain gauge which are respectively arranged at two ends and the periphery of the steel support as required and cling to the underground diaphragm wall steel plate, and the measuring and transmitting system is the underground diaphragm wall steel plate deformation data acquisition equipment.
Further, the control output system comprises a host and a Programmable Logic Controller (PLC), wherein the host is used for processing the collected axial force value and displacement value, giving out a control signal, and the PLC is used for converting the output value into an axial force electric signal and a displacement electric signal after receiving the control signal of the host, mainly using the displacement electric signal, and completing the axial force compensation loading of the steel support through electric signal switch control.
Further, a steel plate is covered on sand on one side of the foundation pit in the test box, and a weight block is placed on the steel plate to apply an eccentric load.
One method of use of the controller platform of the present invention is as follows:
1) Filling sand into an organic glass test box, placing an embedded part, compacting in layers until the top surface of a sand sample is slightly lower than the upper opening surface of the test box, reserving holes at the steel support erection position of the underground diaphragm wall steel plate, installing an optical fiber deformation monitor and a strain gauge at proper positions, and vertically driving into the budget position in the sand.
2) And (3) opening all valves, debugging the water suction pump, and filling all water tanks to ensure that a stable water head with constant water level height in the water injection tank meets the control requirement required by the test.
3) And (3) starting excavation unloading of the earthwork of the foundation pit, and digging out sand among the steel plates of the underground continuous wall by similar layering and blocking until the position of a preset steel support assembly is reached.
4) And respectively installing lower fit sections on the steel plates of the underground continuous walls at two sides of the foundation pit, uniformly coating vaseline with certain thickness on the inner wall, installing the debugged pull-press bidirectional force transducer in the lower fit sections, sequentially installing the steel support main bodies, adding the pressurizing top cover at two ends, coating the vaseline on the pressurizing top cover, and horizontally placing the pressurizing top cover at the lower fit sections until the pressurizing top cover is completely contacted with the surface of the pressure transducer.
5) Solid dowel steel rods extend out of the two sides outside the pit through pre-buried aluminum alloy pipes until the outer side of the test box, cross section expansion end joints are reserved at two ends of each aluminum alloy pipe, the end, close to the foundation pit, is tightly connected with the fixed support, the underground continuous wall steel plate and the fitting section, vaseline is smeared on the contact surface of the other end, a dial indicator is installed at the back and adjusted to a proper position, and after the fitting section is slowly buckled, a sensor lead is led out along the through section.
6) Spring dynamometers are arranged on two sides through tensile steel wires, and then a water bearing tank with scales is connected with the tensile steel wires around pulleys. All electromagnetic valves on the outer wall of the water injection tank are closed, only the highest electromagnetic valve is reserved to be connected with the water drainage tank, water is continuously injected into the water injection tank, redundant water is discharged out of the water injection tank through the electromagnetic valve and the water drainage tank after the water level reaches the electromagnetic valve in an open state, at the moment, a certain hydraulic gradient at two sides of the tank can be formed, and the water inlet head preparation test is easy to stabilize.
7) The method comprises the steps of connecting each sensor and a dynamic data analyzer, installing a PLC core controller, adjusting relevant components of a foundation pit, debugging each instrument through a host, connecting a water bearing tank, opening a valve, converging water in the water bearing tank through an electromagnetic valve, enabling water to flow into the water bearing tank and flow into the water bearing tank with scales through the tail end of a water inlet pipe, closing the water outlet valve of the water bearing tank after water flow is stable, measuring water flow in a certain time, calculating the flow rate of water flow, and further calculating the load ratio under the power and observing indexes of each instrument.
8) After the pre-test is finished, formally loading, firstly filling a common steel plate on one side outside a pit, then applying a weight, then excavating to the next steel support in a layered and block mode, carrying out graded loading until an alarm occurs to a host, always keeping the spring dynamometer in a stressed state in the test process, adjusting the load ratio of two sides, then directly calculating a change value, and finally carrying out test control program correction to reduce errors.
The invention has the following advantages and positive effects:
(1) different axial force setting modes can be set for the same sample group to carry out loading and unloading tests;
(2) for the multi-layer multi-row steel support foundation pit, a fit section erection steel support assembly can be directly installed on an original test device to carry out loading measurement and control, and a rough cloud image of the simulated underground diaphragm wall steel plate structure after being subjected to stress deformation is also clearly visible;
(3) the operation is simple, and the defects that the hydraulic pump jack is adopted for loading, different test devices are required to be adopted for different tests and the like are avoided.
Aiming at the problems that the field test of the existing foundation pit axial force servo system based on active control is difficult to operate, the steps are complicated and the like, the invention provides an integrated entity controller platform for simulating the foundation pit axial force servo control system in a visual, automatic and various setting modes.
Drawings
FIG. 1 is a top view of one example of a bench plexiglass test chamber;
FIG. 2 is a schematic view in section A-A of FIG. 1;
FIG. 3 is a schematic view of the overall structure of an example of the plexiglas test chamber of the present platform;
FIG. 4 is a top view of the present platform tank;
FIG. 5 is a schematic view in section B-B of FIG. 4;
FIG. 6 is a schematic view showing the overall structure of an example of the water filling tank of the present platform;
FIG. 7 is a schematic view of a steel support assembly according to an embodiment;
FIG. 8 is a schematic view of an extended solid steel rod assembly in an embodiment;
FIG. 9 is a schematic view of an upper engaging section and a lower engaging section according to the present invention;
in the figure: 11 is an organic glass test box, 12 is an underground diaphragm wall steel plate, 13 is an optical fiber deformation monitor, 14 is a strain gauge, 15 is an aluminum alloy pipe, 16 is a spring dynamometer, 17 is a dial gauge, 18 is a water filling tank, 19 is a water storage tank, 20 is a water draining tank, 21 is a pressurizing top cover, 22 is a pulley, 23 is a section expanding end joint, 24 is an upper fitting section, 25 is a crosspiece, 26 is an upper fitting strip, 27 is a lower fitting section, 28 is a lower fitting strip, 29 is a supporting leg, 30 is a steel support, 31 is an underground diaphragm wall, 32 is a weight block, 33 is a support, 34 is a steel plate, 35 is a preformed hole, 36 is a drain valve, 37 is a buffer raft, 38 is an overflow seam, 40 is a guide port, 41 is an electromagnetic valve, 42 is a tension and compression bidirectional force transducer, 43 is a spring, 44 is a solid steel rod, 45 is an aluminum alloy sleeve, 46 is an end spring sleeve, 47 support, 48 is a tensile steel wire, 49 is a water bearing tank, and 50 is internally movably connected.
Detailed Description
The invention will be further described with reference to specific drawings and examples, to which the scope of protection of the invention is not limited.
Example 1
As shown in fig. 1, 2 and 3, a set of foundation pit axial force servo system simulation entity controller platform comprises a load system, a measurement transmission system, a control output system, a plexiglass test box 11, a water injection box 18, an optical fiber deformation monitor 13, a strain gauge 14, a pressurizing top cover 21, a support 47, a plurality of connecting pieces and the like.
The load system comprises an eccentric load of the foundation pit and a bearing axial force load of the steel support. The loading is divided into loading and unloading modes, and the two modes are basically the same, wherein the steel support shaft force compensation loading is different, and the loading is divided into one-end loading and two-end loading, and the loading modes are that water is injected into the water bearing tank 49 through the water drainage groove 20, and the loading is converted through the pulley 22. The load system consists of a common steel plate 34, a weight block 32, an end spring sleeve assembly (fig. 7) and a solid steel rod 44 (fig. 8), a spring dynamometer 16, a tensile steel wire 48 (high rigidity), a water-bearing tank 49, and a pulley 22 and a bracket 33.
The measurement transmission system refers to shaft force transmission and displacement transmission. The tension and compression bidirectional force measuring sensor 42 is installed at two ends of the steel support 30, the underground continuous wall steel plate 12 has a through section from bottom to top, and the corresponding upper engaging section 24 and lower engaging section 27 can be manually assembled and disassembled, so that the tension and compression bidirectional force measuring sensor 42 and a fixed steel support assembly can be conveniently placed (fig. 7). The dial indicators 17 are arranged at the two sides of the organic glass test box 11 and the external section expansion end joints 23 are connected with a dynamic data analyzer, and a plurality of connecting pieces are needed.
The control output system is mainly a host and a Programmable Logic Controller (PLC). The host computer carries out the processing of procedure to the axial force value and the displacement value of gathering, gives control signal, and after the PLC received host computer control signal, it is two parts to convert output value into axial force signal and displacement signal, and mainly displacement signal, accomplishes steel backing shaft force compensation loading jointly through electric signal switch control suction pump and solenoid valve 41.
The optical fiber deformation monitor 13 and the strain gauge 14 are all deformation data acquisition devices of the underground diaphragm wall steel plate 12, and are respectively arranged at two ends and the periphery of the steel support 30 as required, cling to the underground diaphragm wall steel plate 12, and are externally connected with a dynamic data analyzer so as to be beneficial to observing the deformation process of the underground diaphragm wall 31 and assisting other data analysis.
The end spring sleeve 46, namely the steel support 30, consists of three sections of aluminum alloy tubes 15 with scales, a spring 43 with scales is arranged in the end spring sleeve, wherein two sections of aluminum alloy tubes are inscribed in a middle section, namely the ends of two sections of aluminum alloy tubes on the edge are connected with the ends of the spring in the middle section, so that the three sections of aluminum alloy tubes form an aluminum alloy sleeve with adjustable length, a middle channel penetrates through the whole axis, and the ends of the three sections are designed into shapes convenient for fixing the spring 43 or installing a connecting piece.
The middle shaft of the pressurizing top cover 21 is provided with a small hole which is arranged at two ends of the steel support 30, the outer diameter of the top cover is slightly smaller than the inner diameter of the aluminum alloy sleeve 45, the diameter of the top cover is slightly larger than that of the solid steel rod 44, one end of the pressurizing top cover is connected with the pulling and pressing bidirectional force measuring sensor 42 through a hollow connecting piece, and the inner end of the pressurizing top cover is internally provided with a loose joint 50 which is connected with the end part of the steel support 30.
As shown in fig. 9, as a specific example of the upper and lower engaging sections, the outer wall of the lower engaging strip 28 of the lower engaging section 27 is welded with a supporting leg, the tail end of the supporting leg is provided with a thread, the lower engaging section 27 can be embedded into the penetrating section of the underground diaphragm wall steel plate 12 until the position of the reserved hole 35 and the outer thread is just tightly connected with the out-pit section expanding end joint 23 through the reserved hole 35. The upper engaging section 24 is formed by welding a top crosspiece 25 and an upper engaging strip 26, the upper engaging section 24 can be embedded into a through section of the diaphragm wall steel plate 12, and the lower part of the upper engaging section 24 is just jointed with a lower engaging section 27 in the through section. The upper and lower engagement sections can also be realized in other ways, as long as the installation of the load cell and the fixing of the steel support can be realized.
As shown in fig. 4, 5 and 6, the outer wall of the water injection tank 18 is provided with a plurality of electromagnetic valves 41 which are distributed at equal intervals along the height, and the stable water head with constant water level of the water injection tank 18 can be controlled according to the test requirement. The drain tank 20 is provided with a row of flow guide ports 40, and the drain tank 20 can collect and drain overflow water from the water tank 18. The outer wall of the water bearing tank 49 is marked with capacity scales, an inclined buffer guide plate is fixed in the water bearing tank, a drain valve 36 is respectively arranged on the upper part and the lower part, the water injection tank 18 is connected on the upper part, and the water storage tank 19 is connected on the lower part.
Example 2 a set of foundation pit axial force servo system simulation entity controller platform as described in example 1, specifically operates as:
1) Filling sand into the organic glass test box 11, placing embedded parts, compacting in layers until the top surface of a sand sample is slightly lower than the upper opening surface of the organic glass test box 11, setting a preformed hole 35 at the erection position of the steel support 30 of the underground diaphragm wall steel plate 12, installing the optical fiber deformation monitor 13 and the strain gauge 14 at a proper position, and vertically driving into the budget position in the sand.
2) All valves are opened, the suction pump is adjusted, and all water tanks are filled, so that the stable water head with constant water level in the water injection tank 18 meets the control requirement required by the test.
3) And (3) starting excavation unloading of the earthwork of the foundation pit, and excavating sand among the steel plates 12 of the underground continuous wall until the position of a preset steel support assembly (figure 7) is reached by similar layering and blocking.
4) The lower engaging sections 27 are respectively arranged on the underground continuous wall steel plates 12 at the two sides of the foundation pit, vaseline with a certain thickness is uniformly smeared on the inner wall, the debugged pulling and pressing bidirectional force transducer 42 is arranged in the lower engaging sections 27, then the steel supporting main body (figure 7) is sequentially arranged, the pressurizing top cover 21 is added at the two ends, and the pressurizing top cover 21 is horizontally placed on the lower engaging sections 27 after being smeared with the vaseline until the pressurizing top cover 21 is completely contacted with the surface of the pulling and pressing bidirectional force transducer 42.
5) Solid dowel steel rods 44 extend out of the pit through the embedded aluminum alloy pipe 15 to the outer sides of the organic glass test box 11, cross section enlarged end joints 23 are reserved at the two ends of the aluminum alloy pipe 15, the end close to the foundation pit is tightly connected with the fixed support 47, the underground continuous wall steel plate 12 and the lower fit section 27, vaseline is coated on the contact surface of the other end, a dial indicator 17 is installed at the rear and adjusted to a proper position, and after the fit section 24 is slowly buckled, a sensor lead is led out along the through section.
6) Spring load cells 16 are mounted on both sides of solid steel bar 44 by tension wires 48, and then graduated water bearing boxes 49 are connected around pulley 22 with tension wires 48. All electromagnetic valves 41 on the outer wall of the water injection tank 18 are closed, only the highest electromagnetic valve 41 is left to be connected with the water drainage tank 20, water is continuously injected into the water injection tank 18, redundant water after the water level reaches the electromagnetic valve 41 in the opened state is discharged into the water injection tank 18 through the electromagnetic valve 41 and the water drainage tank 20, at the moment, a certain hydraulic gradient on two sides of the tank can be formed, and the water inlet head preparation test is easy to stabilize.
7) The method comprises the steps of connecting each sensor and a dynamic data analyzer, installing a PLC core controller, adjusting relevant components of a foundation pit, debugging each instrument through a host, connecting a water bearing tank 49, opening a valve, converging water in a water discharge tank 20 through an electromagnetic valve 41, flowing water in the water discharge tank 18 into the water bearing tank 49 through the tail end of a water inlet pipe, after water flow is stable, closing a water outlet valve of the water bearing tank, measuring water flow in a certain time, calculating the flow rate of the water flow, and further calculating the load ratio under the power and observing indexes of each instrument.
8) After the pre-test is finished, formally loading, firstly filling a common steel plate 34 on one side outside the pit, then applying a standard weight block 32, then excavating to the next steel support 30 in a layered and block mode, carrying out graded loading until the main machine alarms, always keeping the spring dynamometer 16 in a stressed state in the test process, adjusting the load ratio of two sides, then directly calculating a change value, and finally carrying out test control program correction to reduce errors.
The above-mentioned implementation method is merely to fully illustrate the preferred implementation of the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions and changes are within the scope of this patent by those skilled in the art based on this patent. The protection scope of this patent is subject to the claims.
Claims (6)
1. The utility model provides a foundation ditch axial force servo system simulation entity controller platform which characterized in that: the system comprises a test box, a load system, a measurement transmission system and a control output system; the test box is used for containing sand and placing an underground diaphragm wall to simulate foundation pit construction, and the underground diaphragm wall comprises underground diaphragm wall steel plates (12) at two sides and steel supports (30) arranged between the underground diaphragm wall steel plates; the load system can provide eccentric load of the foundation pit and axial force load of the steel support, and the measurement transmission system is used for detecting the applied axial force and displacement of the underground continuous wall steel plate; the control output system is used for processing the collected axial force value and displacement value and giving out a control signal to control the loading condition of the load system;
carrying out steel support axial force compensation simulation by adopting a water injection loading mode at one end or two ends of the steel support; based on the realization of the steel support assembly, the steel support assembly comprises an end spring sleeve (46) and a solid steel rod (44), wherein the end spring sleeve (46) is formed by coaxially arranging three sections of aluminum alloy pipes with scales and with built-in springs (43), two ends of a middle section are externally connected with two other sections so that the three sections of aluminum alloy pipes form a length-adjustable sleeve, a middle channel penetrates through the whole axis, and the solid steel rod (44) is arranged in the middle channel, and two ends of the solid steel rod extend out of a test box through an underground continuous wall steel plate (12); two ends of the solid steel rod (44) are respectively connected with the spring dynamometer (16) through tensile steel wires (48) and then connected with the water bearing tank (49) by bypassing the pulley (22) fixed outside the test box;
the measuring and transmitting system comprises a tension-compression bidirectional force transducer (42), wherein a through section from bottom to top exists on the underground diaphragm wall steel plate (12), the through section is used for being filled with an upper fit section (24) and a lower fit section (27), the upper fit section (24) and the lower fit section (27) are matched for placing and fixing the tension-compression bidirectional force transducer (42), and a section expansion end joint (23) is arranged on the outer section of a solid steel rod (44) which is clung to two sides of the organic glass test box (11) so as to limit and install a dial indicator (17);
the two ends of the steel support (30) are provided with a pressurizing top cover (21), a small hole is formed in the middle shaft of the pressurizing top cover (21), the outer diameter of the top cover is smaller than the inner diameter of the aluminum alloy sleeve, the inner diameter of the top cover is larger than the diameter of a solid steel rod (44), one end of the hollow connecting piece is connected with a tension-compression bidirectional force transducer (42), and the other end of the hollow connecting piece is internally provided with a loose joint (50) connected with the end part of the steel support (30);
the outer wall of a lower fit strip (28) of the lower fit section (27) is welded with a support leg, the tail end of the support leg is provided with threads, the lower fit section (27) can be embedded into a through section of the underground diaphragm wall steel plate (12) until the position of a reserved hole is reached, and the outer threads are tightly connected with a section expansion end joint (23) of the pit outer steel support (30) through the reserved hole.
2. The foundation pit axial force servo system simulation entity controller platform of claim 1, wherein: the upper engaging section (24) is formed by mutually welding a top crosspiece (25) and an upper engaging strip (26), the upper engaging section (24) can be embedded into a through section of the underground diaphragm wall steel plate (12), and the upper engaging section (24) is just jointed with a lower engaging section (27) in the through section.
3. The foundation pit axial force servo system simulation entity controller platform of claim 1, wherein: the outer wall of the water bearing tank (49) is marked with capacity scales, an inclined buffer guide plate is fixed in the water bearing tank, a water discharge valve is respectively arranged at the upper part and the lower part of the water bearing tank, the water bearing tank is connected with the water injection tank (18) at the upper part, and the water storage tank is connected at the lower part; the water injection tank is characterized in that a plurality of electromagnetic valves (41) are uniformly distributed on the outer wall of the water injection tank (18) along the height, a stable water head with constant water level of the water injection tank (18) can be controlled according to test requirements, a drainage groove (20) is arranged below each electromagnetic valve (41), a row of drainage ports (40) are arranged in the drainage groove, and overflow water of the water injection tank can be collected and discharged from the drainage groove.
4. The foundation pit axial force servo system simulation entity controller platform of claim 1, wherein: the measuring and transmitting system comprises an optical fiber deformation monitor (13) and a strain gauge (14), wherein the optical fiber deformation monitor and the strain gauge are respectively arranged at two ends and the periphery of a steel support (30) as required, and are clung to underground continuous wall steel plates (12) and are all deformation data acquisition equipment of the underground continuous wall steel plates (12).
5. The foundation pit axial force servo system simulation entity controller platform of claim 1, wherein: the control output system comprises a host and a Programmable Logic Controller (PLC), wherein the host is used for processing the collected axial force value and displacement value, giving out a control signal, and the PLC is used for converting the output value into an axial force electric signal and a displacement electric signal after receiving the control signal of the host, and mainly uses the displacement electric signal to finish the compensation loading of the steel support axial force through the control of an electric signal switch.
6. The foundation pit axial force servo system simulation entity controller platform of claim 1, wherein: a steel plate (34) is covered on sand on one side of a foundation pit in the test box, and a weight (32) is placed on the steel plate (34) to apply eccentric load.
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