CN104763001A - Testing device and testing method suitable for creep property of anchor cable anchoring segment - Google Patents

Abstract

The invention discloses a test device and test method suitable for the creep characteristics of the anchorage section of the anchor cable, in order to fill the gap in the research on the creep characteristics of the anchorage section of the prestressed anchor cable, and reveal the deformation time between the anchor cable and the grouting body section Effect, a test method and test device suitable for the creep characteristics of the anchorage section of the anchor cable are proposed. Based on the space axisymmetric equilibrium differential equation, physical equation and geometric equation, the similarity relationship of each parameter is proposed, and the similarity ratio of the model test is formulated. The test device consists of prestressed anchor cables (ribs), loading jacks, anchor devices, anchor cable gauges, reaction frames, grouting bodies, model grooves and anchor bolts from top to bottom. The monitoring device is composed of a dial indicator and a strain gauge. The device can not only simulate the creep test of the anchorage section, but also perform the pullout test of the anchor cable (rod).

Description

A test device and test method suitable for the creep characteristics of the anchorage section of the anchor cable

technical field

The invention belongs to the technical field of geotechnical engineering, and in particular relates to an indoor model test device and a test method for anchor cable creep.

Background technique

Prestressed anchorage technology has increasingly become the preferred method in slope reinforcement engineering because of its advantages of small disturbance to rock and soil, fast construction, and economy, and has achieved huge economic and social benefits. This efficient and economical prestressed reinforcement technology has also been widely used in other civil engineering fields, such as tunnels, ship locks, dams, underground powerhouses, deep foundation pits and other projects, and is mostly used as permanent support measures. It is used in some projects with higher safety requirements. However, affected by factors such as prestress level, anchoring technology, material mechanical properties and creep, the prestress of the anchor cable will be lost or even fail. The first three influencing factors have nothing to do with the time effect. Scholars at home and abroad have also done a lot of experimental research. However, the research on creep characteristics is limited to the creep deformation law of the rock mass around the anchorage section under high prestress load, and the research on the creep characteristics of the interface between the anchor cable and the grouting body in the anchorage section has not yet been carried out. , the present invention fills the gap in the research on the creep characteristics of the anchorage section of the prestressed anchor cable, reveals the deformation time effect between the anchor cable and the grouting body interface, and proposes a test method and test method suitable for the creep characteristics of the anchorage section of the anchor cable. device.

In the patent application number [201310476174.0], a non-metallic anti-floating bolt creep test loading device is disclosed. Although the device can effectively load the bolt, the jack cannot be taken out after the device is loaded, and Under normal circumstances, the jack itself will produce oil return under long-term load, that is, the reaction force provided by the jack will become smaller and smaller, causing the test load to be smaller than the design load, which will affect the accuracy of the test; at the same time, the reaction beam is made of I-beam. The beam bending rigidity is large, but mid-span bending will still occur under the action of high stress load; moreover, the test device can only load one anchor cable at a time, and the creep of the anchor cable is a time-dependent process. The time is long, so the creep test efficiency of the device is low.

Contents of the invention

In order to overcome the deficiencies of prior art theory and experimental research, the present invention proposes a test method and test device suitable for the creep characteristics of the anchorage section of the prestressed anchor cable.

The technical scheme that the present invention adopts is as follows:

A test device suitable for the creep characteristics of the anchorage section of the prestressed anchor cable, including a model groove, the model groove includes two devices arranged in parallel and vertically fixed with anchor cables, and fixed at the ends of the two anchor cables There is a strain gauge for testing its deformation. One end of the two anchor cables is fixed in the model groove through the grouting body, and the other end passes through the reaction frame fixed above the model groove. After one of the anchor cables passes through the reaction frame, An anchor cable gauge and anchor bolts are installed on it; after the other anchor cable passes through the reaction frame, an anchor cable gauge, a piercing jack, a pressure sensor and anchor bolts are installed on it.

The anchor cable meter is fixed on the top of the reaction force frame through anchor bolts.

The through-hole jack is fixed on a jack bracket, and the jack bracket is fixed on the top of the reaction frame.

The pressure sensor is fixed on the top of the jack through anchor bolts.

The model groove includes two cylindrical cylinders, the two cylinders are connected into an integral structure by welding, and a hole for installing an anchor screw is reserved at the bottom of each cylinder.

Bolts are used to fix the anchor screw in the hole of the cylinder at the bottom of the cylinder, and then the hole is sealed with epoxy resin.

Two support plates are arranged on both sides of the model groove, and the support plates are connected with the reaction frame above them.

The top of the model groove is provided with a dial gauge.

Above-mentioned device test content comprises anchor cable (rod) prestress change rule with time, anchor section anchor cable (rod) creep, grouting body deformation and anchor rod free section deformation; Described anchor rod prestress is measured by anchor cable meter, The deformation of the anchoring section and the free section is measured by sticking a strain gauge on the surface of the anchor cable (rod), and the deformation of the grouting body is measured by setting a fixed dial gauge on its surface.

The test method of the above-mentioned device is as follows:

Step 1: Determine each component according to the similarity relationship between the test device and the actual model;

Step 2 Connect the model tank and the reaction frame as a whole, fix the anchor screw on the cylinder bottom of the model tank with bolts, and then seal the hole at the bottom of the cylinder with epoxy resin;

Step 2 Place an anchor cable with a strain gauge attached to the center of the cylinder, and the upper part of the anchor cable is first fixed on the reaction frame by anchor bolts;

Step 3 pouring the grout in the cylinder, and the model after pouring is placed under standard conditions for curing for the set time;

Step 4: After the test piece is cured, prestress tension is carried out, and the rigid block, anchor cable meter, lower anchor bolt, jack bracket, through-hole jack, pressure sensor and upper anchor bolt are placed in sequence on the reaction frame, and the A dial gauge for measuring the displacement of the grouting body is installed on the top of the tank;

Step 5: Tighten the upper anchor bolt first, keep a certain distance between the lower anchor bolt and the backing plate, conduct a strain test, perform prestress tension according to the design prestress level, and tighten the lower anchor bolt after reaching the design load, and unload the through jack prestress;

Step 6: Measure the load on the anchor cable meter and compare it with the design load. If the difference between the two exceeds 100N, re-tension. At this time, increase the load during tension to offset the loss of prestress during anchoring. The process should be Repeat until the design requirements are met;

Step 7: After the prestress tension is completed, measure the strain of the anchor cable in the anchorage section and the top displacement of the grouting body, and then measure the strain of the steel bar every other day.

The test content in the test method includes the change rule of the prestress of the anchor cable (rod) with time, the creep of the anchor cable (rod) in the anchor section, the deformation of the grouting body and the deformation of the free section of the anchor bar.

The prestress of the anchor rod is measured by an anchor cable gauge, the deformation of the anchor section and the free section is measured by sticking a strain gauge on the surface of the anchor cable (rod), and the deformation of the grouting body is measured by setting a fixed dial gauge on the surface.

The determination method of the similarity relationship in step 1 is as follows:

In order to ensure the accuracy of the test results, the test model should determine the geometric dimensions according to the geometric similarity conditions, and formulate corresponding test methods according to the test content. The similarity conditions of the present invention are as follows:

The physical quantities related to this experiment mainly include

Where: L: geometric dimension; ε: strain; δ: deformation; μ: Poisson’s ratio; γ: material weight; c: cohesion; Friction angle; E: elastic modulus; σ: stress; t: time.

The subscript "p" represents the prototype, and "m" represents the model, then the ratio of the performance parameters of the prototype to the model can be expressed as: (The meaning of the parameters has been given) The similarity ratio of the rest of the basic mechanical properties of the material is 1;

In the formula:

C _L : Prototype and model geometric similarity ratio;

C _E : Prototype and model elastic modulus similarity ratio;

C _σ : Prototype and model stress similarity ratio;

C _t : Prototype and model time similarity ratio;

C _γ : Prototype and model heavy similarity ratio;

L _p , L _m : Prototype and model geometry;

E _P , E _m : prototype and model elastic modulus;

σ _P , σ _m : prototype and model stresses;

t _P , t _m : prototype and model time;

γ _P , γ _m : prototype and model weights.

The prestressed anchor cable creep test model is a space axisymmetric structure, and the prototype space axisymmetric balance differential equation:

${<span\; class="notranslate">\; (</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; \&rho;z</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; \&rho;z</span>}}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; )</span>}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$

Model space axisymmetric equilibrium differential equation:

${<span\; class="notranslate">\; (</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; \&rho;z</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; \&rho;z</span>}}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; )</span>}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$

compare the similarity Bringing into the axisymmetric equation of the prototype space, the simplification is:

${<span\; class="notranslate">\; (</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; \&rho;z</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; \&rho;z</span>}}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}}{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; )</span>}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$

Comparing the simplified equation with the axisymmetric equilibrium differential equation in model space, it can be concluded that:

C _L C _γ = C _σ ,

For the same reason, the geometric equations and physical equations of the space axisymmetric problem can be drawn as follows:

C _L C _ε = C _δ , C _E C _ε = C _σ

In the formula:

C _ε : Prototype and model strain similarity ratio;

C _δ : Prototype and model deformation similarity ratio;

In the present invention, the length similarity ratio of the anchorage section of the test device and the original model is 1:10;

The time effect similarity ratio is

The diameter of the anchor cable and the geometric similarity ratio of the diameter of the grouting body are 1:1;

The stress similarity ratio of the anchor cable is 1:10,

The interface deformation similarity ratio of reinforcement and grouting body is 1:10.

Beneficial effects of the present invention:

1. The present invention proposes a test method and test model for the creep characteristics of the anchorage section, which can be used for the experimental research on the creep characteristics between the prestressed anchor cable (rod) and the grouting body section, and based on similar conditions, a reasonable test model is formulated Basic parameter similarity ratio.

2. Formulate the test method for the deformation time effect between the interface between the grouting body and the prestressed anchor cable (rod) in the creep test of the anchorage section.

3. The model groove of the present invention is an assembled structure. In addition to the creep characteristic test of the anchorage section of the prestressed anchor cable, it can also study the prestress loss and failure mechanism of the anchorage structure under the synergistic effect of prestress and anchorage rock mass creep. . At the same time, the ultimate pullout model test research of prestressed anchor cables (rods) can be carried out.

4. The device is a creep test of the anchorage section of the anchor cable under the same working conditions. The anchor cables on the left and right are parallel tests for comparison. Schematic diagram of the process; during the test, the same preload is applied to the two anchor cables, and then the test data is collected. Under the same test conditions, the loading results can be compared and the error value can be observed.

Description of drawings

Fig. 1 is the front view of the anchor section creep test device;

Fig. 2 is a three-dimensional diagram of the anchor section creep test device;

Figure 3 is a schematic diagram of the pullout test of the anchor cable;

In the figure: 1. Anchor bolt, 2. Pressure sensor, 3. Piercing jack, 4. Jack bracket, 5. Steel backing plate, 6. Anchor cable gauge, 7. Reaction frame, 8. Anchor cable, 9. Thousand Sub-table, 10. Cylinder, 11. Anchor screw, 12. PVC pipe.

detailed description

Below in conjunction with accompanying drawing, the technical scheme of the present invention is further supplemented explanation:

A test method and test device suitable for the creep characteristics of the anchor section of the prestressed anchor cable. The test device includes a prestressed anchor cable from top to bottom, a loading jack, an anchor device, an anchor cable meter, a reaction frame, a grouting body, Composed of model slots and anchor bolts. The monitoring device is composed of a dial indicator and a strain gauge.

The model tank includes two cylinders 10 arranged in parallel and vertically fixed with anchor cables. Strain gauges are fixed at the ends of the two anchor cables to test their deformation. One end of the two anchor cables is fixed in the model groove by grouting fluid. Inside, the other ends pass through the reaction force frame 7 fixed above the model groove, after one of the anchor cables 8 passes through the reaction force frame 7, an anchor cable meter 6 is installed on it; the other anchor cable 8 passes through the reaction force After the frame 7, the anchor cable meter 6, the through jack 3 and the pressure sensor 2 are installed on it; the anchor cable meter 6 is fixed on the top of the reaction force frame 7 by the anchor bolt 1.

The pressure sensor 2 is fixed on the top of the jack by anchor bolts.

The two cylinders 10 are connected by welding to form an integral structure, and a hole for installing an anchor screw 11 is reserved at the bottom of each cylinder.

Fix the anchor screw in the hole of the cylinder with bolts at the bottom of the cylinder, and then seal the hole with epoxy resin.

Two support plates are arranged on both sides of the model groove, and the support plates are connected with the reaction frame above them.

The top of described model groove is provided with dial gauge 9.

The diameter of prestressed anchor cables (ribs) is between 5 and 30 mm, and the prestressed anchor cables are 1 to 7 bundles, which are fixed by anchor heads; the prestressed anchor tendons are fixed by bolts, and the lower part is provided with perforated spacers;

The loading jack is a horizontal penetrating jack 3, the maximum loading reaction force is not less than 300kN, and the corresponding anchor cable is not less than 300kN; the penetrating jack 3 is fixed on a jack bracket 4, and the jack bracket 4 is fixed on the reaction force frame 7 the top of.

The reaction force frame 7 is made of high-quality carbon structural steel with a length of 1m and a height of 30cm to 50cm. The shape of the beam is "I" and its width is 20cm. A hole is punched at the center of the model groove with a diameter of 10 to 30mm. , each reaction frame is provided with 3 vertical support structures, which are connected to the bottom model groove by bolts.

The model tank is two cylindrical structures, the material of which is Q235 ordinary steel, the wall thickness is 15-20mm, the diameter of the cylinder is 30-50cm, and the height is 40-50cm. The two cylinders are connected by welding to form an overall structure. , 4 holes with a diameter of 10-20mm are reserved at the bottom, and 4 diagonal braces are set between the bottom and the side wall of the cylinder. The outside of the cylinder is welded to the steel plates on both sides, and connected to the reaction frame by bolts.

The specific test method is as follows:

1. Use the device in Figure 3 to perform a pullout test on the prestressed anchor cable, as follows:

As shown in Figure 3, the device suitable for the pullout test of prestressed anchor cables mainly includes 10 cylinders and 7 reaction frames. The outer side of the cylinder 10 is welded to the steel plates on both sides, and connected to the reaction frame 7 by bolts. Four holes with a diameter of 10-20 mm are reserved at the bottom of the cylinder 10 for placing the 11 anchor screw; the experimental method is as follows:

Step 1: First, the cylinder 9 and the reaction frame 7 should be connected as a whole by bolts, the anchor screw 11 is fixed on the cylinder 10 with bolts at the bottom of the cylinder 10, and then the four holes at the bottom of the cylinder 10 are sealed with epoxy resin. Do sealing treatment;

Step 2 After the anchor screw 11 is installed, place the PVC pipe 12 at the center, seal the bottom with epoxy resin, and pour the surrounding simulated rock mass;

Step 3 After the simulated rock mass reaches a certain strength, the PVC pipe 12 is taken out, and the anchor cable (rod) 8 with a strain gauge attached is placed in the center of the cylinder 10. In order to ensure that the body does not deviate from the center position, the upper part of the anchor cable (rod) 8 should be First fix it on the reaction frame 7 through the anchor bolt 1;

Step 4 pouring the grouting body in the cylinder 10, the height of the grouting body is 40cm, and the model after pouring should be placed under standard conditions (constant temperature and humidity) for 28 days of curing.

Step 5 After the test piece is cured to 28, the pull-out test of the anchor cable (rod) 8 is carried out, the core jack 3, the pressure sensor 3 and the upper anchor bolt 1, the anchor bolt 1 should be tightened first, and the thousandth 9 is installed to measure Grouting body displacement and bolt displacement.

Step 5 Before tensioning, carry out the strain test first, and carry out the pull-out test according to the cyclic loading method.

2. Using the device as shown in Figure 1 and Figure 2 to carry out the creep model test of the anchorage section of the prestressed anchor cable

As shown in Figure 1 and Figure 2, the test device suitable for the creep characteristics of the anchorage section of the prestressed anchor cable mainly includes 10 cylinders and 7 reaction force frames. The outer side of the cylinder 10 is welded to the steel plates on both sides, and the Power frame 7 is connected. Four holes with a diameter of 10-20 mm are reserved at the bottom of the cylinder 10 for placing the 11 anchor screw. The specific test steps are as follows:

Step 1. First, the cylinder 9 and the reaction frame 7 should be connected as a whole by bolts, the anchor screw 11 is fixed on the cylinder 10 with bolts at the bottom of the cylinder 10, and then the four bottoms of the cylinder 10 are fixed with epoxy resin. The holes are sealed;

Step 2. After the anchor screw 11 is installed, place the anchor cable (rod) 8 with a strain gauge attached to the center of the cylinder 10. In order to ensure that the body does not deviate from the center position, the upper part of the anchor cable (rod) 8 should first pass through the anchor bolt 1 fixed on the reaction frame 7;

Step 3. Pour the grout in the cylinder 10. The height of the grout is 40cm. After the pouring is completed, the model should be placed under standard conditions (constant temperature and humidity) for 28 days of curing.

Step 4. After the specimen is cured to 28°C, perform prestressed tensioning. On the reaction force frame 7, place rigid pads 5, anchor cables 7, lower anchor bolts 1, jack brackets 4, through-hole jacks 3, and pressure sensors. 3 and the upper anchor bolt 1 and install a dial gauge 9 to measure the displacement of the grouting body.

Step 5. Tighten the upper anchor bolt 1 first, and keep a certain distance between the lower anchor bolt 1 and the backing plate 5. Before tensioning, the strain test should be carried out first, and the prestress tension should be carried out according to the design prestress level. After reaching the design load, tighten Lower the anchor bolt 1, and unload the upper prestress of the through jack 3.

Step 6. Measure the load on the anchor cable meter 5 and compare it with the design load. If the difference between the two exceeds 100N, re-tensioning should be carried out. At this time, the load during tension should be increased to offset the loss of prestress during anchoring , this process should be repeated until the design requirements are met.

Step 7. After the prestress tension is completed, measure the strain of the steel bar at the anchorage section and the top displacement of the grouting body, and then measure the strain of the steel bar every other day.

The determination method of the similarity relationship in step 1 is as follows:

In order to ensure the accuracy of the test results, the test model should determine the geometric dimensions according to the geometric similarity conditions, and formulate corresponding test methods according to the test content. The similarity conditions of the present invention are as follows:

The physical quantities related to this experiment mainly include

Where: L: geometric dimension; ε: strain; δ: deformation; μ: Poisson’s ratio; γ: material weight; c: cohesion; Friction angle; E: elastic modulus; σ: stress; t: time.

The subscript "p" represents the prototype, and "m" represents the model, then the ratio of the performance parameters of the prototype to the model can be expressed as: (The meaning of the parameters has been given) The similarity ratio of the rest of the basic mechanical properties of the material is 1;

In the formula:

C _L : Prototype and model geometric similarity ratio;

C _E : Prototype and model elastic modulus similarity ratio;

C _σ : Prototype and model stress similarity ratio;

C _t : Prototype and model time similarity ratio;

C _γ : Prototype and model heavy similarity ratio;

L _p , L _m : Prototype and model geometry;

E _P , E _m : prototype and model elastic modulus;

σ _P , σ _m : prototype and model stresses;

t _P , t _m : prototype and model time;

γ _P , γ _m : prototype and model weights.

The prestressed anchor cable creep test model is a space axisymmetric structure, and the prototype space axisymmetric balance differential equation:

${<span\; class="notranslate">\; (</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; \&rho;z</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; \&rho;z</span>}}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; )</span>}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$

Model space axisymmetric equilibrium differential equation:

${<span\; class="notranslate">\; (</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; \&rho;z</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; \&rho;z</span>}}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; )</span>}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$

compare the similarity Bringing into the axisymmetric equation of the prototype space, the simplification is:

${<span\; class="notranslate">\; (</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; \&rho;z</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; \&rho;z</span>}}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}}{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; )</span>}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$

Comparing the simplified equation with the axisymmetric equilibrium differential equation in model space, it can be concluded that:

C _L C _γ = C _σ ,

For the same reason, the geometric equations and physical equations of the space axisymmetric problem can be obtained:

C _L C _ε = C _δ , C _E C _ε = C _σ

In the formula:

C _ε : Prototype and model strain similarity ratio;

C _δ : Prototype and model deformation similarity ratio.

Although the specific implementation of the present invention has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims (10)

1. A test device applicable to the creep characteristics of the anchorage section of the anchor cable, is characterized in that: it comprises a model groove, and the model groove comprises two devices arranged in parallel and vertically fixed with the anchor cable, and the two anchor cables Both ends are fixed with strain gauges for testing their deformation. One end of the two anchor cables is fixed in the model groove by grouting fluid, and the other end passes through the reaction frame fixed above the model groove. One of the anchor cables passes through the reaction frame. After the force frame, an anchor cable meter is installed on it; after the other anchor cable passes through the reaction force frame, an anchor cable meter, a piercing jack and a pressure sensor are installed on it. 2. The test device according to claim 1, characterized in that: said anchor cable meter is fixed on the top of the reaction force frame by anchor bolts. 3. The test device according to claim 1, characterized in that: said through-hole jack is fixed on a jack bracket, and said jack bracket is fixed on the top of the reaction force frame. 4. The test device according to claim 1, wherein the pressure sensor is fixed on the top of the jack by anchor bolts. 5. The test device according to claim 1, characterized in that: the model tank comprises two cylindrical cylinders, which are connected into an integral structure by welding between the two cylinders, and at the bottom of each cylinder Holes are reserved for mounting anchor screws. 6. The test device according to claim 5, characterized in that: the bottom of the cylinder fixes the anchor screw in the hole of the cylinder with bolts, and then seals the hole with epoxy resin. 7. The test device according to claim 1, characterized in that two support plates are arranged on both sides of the model tank, and the support plates are connected with the reaction frame above them. 8. The test device suitable for creep characteristics of the anchorage section of the prestressed anchor cable according to claim 1, characterized in that: the top of the model groove is provided with a dial indicator. 9. The test device according to claim 1, characterized in that: the similarity relationship between the test device and the actual model is: C _L C _γ = C _σ , C _L C _ε = C _δ , C _E C _ε = C _σ ; Among them: C _L : Prototype and model geometric similarity ratio; C _E : Prototype and model elastic modulus similarity ratio; C _σ : Prototype and model stress similarity ratio; C _t : Prototype and model time similarity ratio; C _γ : Prototype and model Model heavy similarity ratio, C _ε : similarity ratio of prototype to model strain; C _δ : similarity ratio of prototype to model deformation. 10. the test method of test device as claimed in claim 9, is characterized in that: Step 1 is to determine each component according to the similarity relationship between the experimental device and the actual model; Step 2 Connect the model tank and the reaction frame as a whole, fix the anchor screw on the cylinder bottom of the model tank with bolts, and then seal the hole at the bottom of the cylinder with epoxy resin; Step 2 Place an anchor cable with a strain gauge attached to the center of the cylinder, and the upper part of the anchor cable is first fixed on the reaction frame by anchor bolts; Step 3 pouring the grout in the cylinder, and the model after pouring is placed under standard conditions for curing for the set time; Step 4: After the test piece is cured, prestress tension is carried out, and the rigid block, anchor cable meter, lower anchor bolt, jack bracket, through-hole jack, pressure sensor and upper anchor bolt are placed in sequence on the reaction frame, and the A dial gauge for measuring the displacement of the grouting body is installed on the top of the tank; Step 5: Tighten the upper anchor bolt first, keep a certain distance between the lower anchor bolt and the backing plate, conduct a strain test, carry out prestress tension according to the design prestress level, after reaching the design load, tighten the lower anchor bolt, and unload the through jack prestress; Step 6: Measure the load on the anchor cable meter and compare it with the design load. If the difference between the two exceeds 100N, re-tension. At this time, increase the load during tension to offset the loss of prestress during anchoring. The process should be Repeat until the design requirements are met; Step 7: After the prestress tension is completed, measure the strain of the anchor cable in the anchorage section and the top displacement of the grouting body, and then measure the strain of the steel bar every other day.