阅读说明：本技术 一种锚-土界面性能室内加速退化试验装置及使用方法 (Indoor accelerated degradation test device for performance of anchor-soil interface and using method ) 是由 陈昌富 朱世民 毛凤山 蔡焕 李伟 吕晨阳 于 2021-08-20 设计创作，主要内容包括：本发明公开了一种锚-土界面性能室内加速退化试验装置及使用方法,试验装置包括围压系统、荷载循环系统、温度循环系统、干湿循环系统。围压系统包括有底盘、套筒、顶板和柔性隔水层,四者之间形成压力室；试样顶部设置“T”形通气件,通气件与抽气机之间设置有多个阀门,试样底部连通有饱和水筒；压力室内安装有与恒温水循环仪连通的不锈钢盘管。本发明可有效模拟围压、干湿循环、温度循环和荷载循环等环境因素对锚-土界面性能的影响,符合工程锚杆的现场服役环境,使得试验数据更为准确有效。配合多种测试传感器,对环境情况进行调控和模拟,整套试验装置可实现自动控制,可用以测取室内人工加速环境下锚-土界面性能退化规律。(The invention discloses an indoor accelerated degradation test device for anchor-soil interface performance and a using method. The confining pressure system comprises a chassis, a sleeve, a top plate and a flexible water-resisting layer, and a pressure chamber is formed between the chassis, the sleeve, the top plate and the flexible water-resisting layer; the top of the sample is provided with a T-shaped ventilation piece, a plurality of valves are arranged between the ventilation piece and the air pump, and the bottom of the sample is communicated with a saturated water cylinder; and a stainless steel coil communicated with a constant-temperature water circulator is arranged in the pressure chamber. The invention can effectively simulate the influence of environmental factors such as confining pressure, dry-wet cycle, temperature cycle, load cycle and the like on the performance of the anchor-soil interface, and conforms to the field service environment of the engineering anchor rod, so that the test data is more accurate and effective. The whole set of test device can realize automatic control and can be used for measuring the performance degradation rule of the anchor-soil interface under the indoor artificial acceleration environment.)

1. An indoor accelerated degradation test device for performance of an anchor-soil interface is characterized by comprising a chassis (202), wherein a sleeve (203) is arranged on the chassis (202), a top plate (204) is connected above the sleeve (203), a flexible water-resisting layer (106) is further arranged on the chassis (202), and a pressure chamber (201) is formed among the chassis (202), the flexible water-resisting layer (106), the sleeve (203) and the top plate (204); an exhaust valve (204a) is arranged on the top plate (204); the pressure chamber (201) is communicated with an air compressor (209); an anchoring unit body test sample (101) is arranged in the flexible waterproof layer (106), the lower end of the anchoring unit body test sample (101) is connected with a load circulating system, and a temperature circulating system is arranged outside the flexible waterproof layer (106); the inner side of the flexible water-resisting layer (106) is communicated with a dry-wet circulation system.

2. The indoor accelerated degradation test device of the performance of the anchor-soil interface of claim 1, wherein the load circulating system comprises a reaction frame (301), a pressurizing device (302) is mounted on the reaction frame, and the pressurizing device (302) is connected with a controller (401) in a wired or wireless mode; a connecting rod (304) is arranged in the pressurizing device (302), and the connecting rod (304) is connected with the anchoring unit body sample (101) through a connecting head (303) above; the pressurization device (302) comprises a hollow hydraulic cylinder.

3. The indoor accelerated degradation test device for the performance of the anchor-soil interface according to claim 1, wherein the temperature circulating system comprises a coil (307) and a first temperature probe (404) for monitoring the external temperature of the anchoring unit body sample (101), the two ends of the coil (307) are connected with the constant-temperature water ring instrument (306), the coil (307) and the constant-temperature water ring instrument (306) form a circulating loop, and a fifth valve (314) is arranged between the constant-temperature water ring instrument (306) and the coil (307); the coiled pipe (307) is wound on the outer side of the flexible water-resisting layer (106); the outer wall of the sleeve (203) is provided with a heat insulation layer (205).

4. The indoor accelerated degradation test device of anchor-soil interface performance of claim 1, wherein the dry-wet circulation system comprises an upper permeable stone (102) and a lower permeable stone (103) arranged in a flexible water barrier (106); a first water content sensor (406) is arranged on the inner side surface of the flexible waterproof layer (106); the lower permeable stone (103) is communicated with a saturated water cylinder (309) through a water inlet channel on the chassis (202), and a first valve (310) is arranged between the saturated water cylinder (309) and the chassis (202); the saturated water cylinder (309) is communicated with the air compressor (209), and a second pressure gauge (410) and a second pressure regulating valve (409) are arranged between the saturated water cylinder (309) and the air compressor (209); an air vent piece (208) is fixed on the top plate (204), and the air vent piece (208) is provided with an air outlet hole (208a) and an air inlet hole (208 b); the air outlet (208a) is communicated with an air extractor (308), and a third valve (312) is arranged between the air outlet (208a) and the air extractor (308); the air pump (308) is also communicated with the lower permeable stone (103) through a water outlet channel of the chassis (202), and a second valve (311) is arranged between the air pump (308) and the chassis (202); and a fourth valve (313) is arranged on the air vent pipeline of the air inlet hole (208 b).

5. The anchor-soil interface performance indoor accelerated degradation test device according to claim 1, wherein silica gel sheets (105) are arranged between the upper permeable stone (102), the lower permeable stone (103) and the rock-soil body (101a), and steel sheets (104) with holes are arranged on the outer sides of the silica gel sheets (105).

6. The device for indoor accelerated degradation test of the performance of the anchor-soil interface, according to claim 1, is characterized in that: the section of the ventilation piece (208) is T-shaped, the outer diameter of the lower sealing circular plate (208f) is equal to that of the rock/adobe (101a), the upper part of the ventilation piece is provided with a thread (208e) which can be matched with the nut (213), and the bottom of the ventilation piece is provided with an annular groove (208 d).

7. A test method for accelerated degradation of anchor-soil interface performance in an indoor artificial environment is characterized by comprising the following steps:

the method comprises the following steps: and (3) sample installation: installing an anchoring unit body sample (101) in the center of a pressure chamber (201), wrapping a flexible waterproof layer (106) and a rubber ring (107) on the periphery of the sample, and leading out wires of a second temperature probe (405) and a first water content sensor (406) from a wire outlet hole (208 c);

step two: applying confining pressure: starting an air compressor (209), filling the pressure chamber (201) with water, closing an exhaust valve (204a), and regulating and stabilizing the pressure output by the pressure chamber (201) to a set confining pressure sigma by a first pressure regulating valve (407)_v；

Step three: carrying out an indoor accelerated degradation test: placing the cured anchoring unit body sample (101) into a flexible waterproof layer (106), connecting the lower end of the anchoring unit body sample (101) with a supercharging device (302), connecting a displacement meter (402) at the lower end of the anchoring unit body sample (101), and carrying out an indoor accelerated degradation test of the mechanical characteristics of the anchor rod interface under the simulated field environment condition according to the set confining pressure, load cycle, temperature cycle and dry-wet cycle;

step four: and (3) drawing test: after the test time of the anchoring unit body sample (101) reaches the designed test time in an indoor artificial accelerated degradation environment, the control instrument (401) is utilized to control the pressurizing device (302), the rod body (101c) is loaded in a force-controlled manner, a drawing force-drawing displacement curve is measured and converted into an anchor-soil interface shear stress tau-shear displacement s curve.

Technical Field

The invention relates to an anchoring support technology frequently used in projects such as side slopes, foundation pits, tunnels, mines, traffic and the like, in particular to an indoor accelerated degradation test device for anchor-soil interface performance and a use method.

Background

Because of the advantages of low cost, simple and convenient construction, mature technology and the like, anchor support technologies such as anchor rods (cables) and the like are widely applied to the rock engineering fields of foundation pit support, tunnel support, underground structure anti-floating, slope anchoring and the like. The mechanical property of the rock-soil body-anchoring body interface determines the engineering property of the rock-soil anchoring structure in service. However, the field environment conditions of the geotechnical anchoring structures are mostly very severe, and the geotechnical anchoring structures are subjected to the cyclic action of various natural environment factors (such as humidity, temperature, precipitation, evaporation and the like) and load factors during service, which causes the mechanical properties of the anchor-soil interface to gradually degrade, and further causes the engineering properties of the geotechnical anchoring structures in service to degrade. Therefore, the mechanical property degradation rule and model of the anchor-soil interface under the field environment condition are the key of long-term performance evaluation and bearing capacity prediction of the rock-soil anchor structure in service.

For a permanent anchoring project, because the service life is long (20-50 years) and the safety requirement is high, the degradation rule of the bearing performance or the mechanical performance of the anchor-soil interface of the anchor rod under the circulating action of field environmental factors (load, temperature, humidity and the like) is directly obtained through a long-period field test, and the long-period field test is time-consuming, labor-consuming and even impossible.

Although the tests can be used for testing the mechanical property of an anchor-soil interface and can also ensure that the mechanical state of a sample is close to the actual field condition of an anchor rod in the testing process, the tests cannot realize the degradation simulation of the sample under the continuous action of complex service environment conditions such as load circulation, temperature circulation, dry-wet circulation and the like. Therefore, the degradation law of the mechanical properties of the anchor-soil interface cannot be obtained by using the existing test technology.

Chinese mainland patent CN107268637A discloses a test system and method for testing mechanical properties of an anchoring interface of a bolt or an anchor cable in a high stress environment. The test system comprises an anchor rod or anchor cable clamping mechanism for testing, an annular high-pressure loading air bag and a flexible restraint hoop sleeve, wherein the anchor rod or anchor cable clamping mechanism is installed at the upper end of a counter-force device, the loading of surrounding rock stress uniformly distributed on the surface of a cylindrical anchoring body model can be realized, and the effective test of the interface mechanical property of the anchor rod or anchor cable anchoring body model under different surrounding rock stress states and loading modes can be met by matching a pneumatic oil tank pump, a high-pressure air pump and a controller.

Chinese continental patent CN102621010B discloses a multifunctional testing machine for deep surrounding rock anchoring performance, which comprises a servo hydraulic control system, an anchoring body vertical tension and compression system, a horizontal shearing system and an anchor rod and anchor cable shearing system, effectively simulates supporting under the condition of underground cavern surrounding rock fracture deformation, especially considers the coupling effect of an anchor rod, an anchor cable and a supporting member with the surrounding rock anchoring body, has rich testing functions, and can more truly reflect the deformation rule of the underground engineering surrounding rock.

However, the existing anchoring performance tests are single mechanical performance tests, the field working environment of anchoring engineering (such as high and steep slope anchoring engineering, underground structure anti-floating anchoring engineering and tunnel shotcrete supporting engineering) is not considered, and the field working environment is mostly very severe, and the cycle action of natural environment factors (such as humidity, temperature, precipitation, evaporation and the like) and load factors can be generated. These environmental factors are critical in practical engineering and they can cause the mechanical properties of the bolt interface to gradually degrade. For the permanent anchoring engineering, because of long service life and high safety requirement, the test of the degradation rule of the mechanical property parameters of the anchor rod interface under the circulating action of field environmental factors (load, temperature, humidity and the like) is necessary.

In order to improve the test efficiency, the artificial environment conditions constructed in the indoor test are usually worse than the actual environment conditions on site, so as to ensure that the mechanical properties of the sample can be degraded to the state of dozens of years of actual environment action on site in a short time. Thus, for the anchor-soil interface, the degradation rules of the mechanical properties of the anchor-soil interface in an indoor artificial acceleration environment and a field environment are different. However, at present, no method exists at home and abroad for calculating the mechanical property degradation rule of the anchor-soil interface under the condition of the on-site service environment by using the test result under the indoor artificial environment aiming at the anchor-soil interface of the rock-soil anchoring structure.

Disclosure of Invention

The invention aims to overcome the defects of the technology and provides an anchor-soil interface performance indoor accelerated degradation test device and a use method thereof aiming at a serving rock-soil anchoring structure.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

an indoor accelerated degradation test device for performance of an anchor-soil interface is characterized by comprising a chassis, wherein a sleeve is arranged on the chassis, a top plate is connected above the sleeve, a flexible waterproof layer is further arranged on the chassis, and a pressure chamber is formed among the chassis, the flexible waterproof layer, the sleeve and the top plate; an exhaust valve is arranged on the top plate; the pressure chamber is communicated with an air compressor; an anchoring unit body sample is arranged in the flexible water-resisting layer, the lower end of the anchoring unit body sample is connected with a load circulating system, and a temperature circulating system is arranged outside the flexible water-resisting layer; the inner side of the flexible water-resisting layer is communicated with a dry-wet circulating system.

The load circulating system comprises a reaction frame, a supercharging device is arranged on the reaction frame, and the supercharging device is connected with a controller in a wired or wireless manner; a connecting rod is arranged in the pressurizing device and is connected with the anchoring unit body sample through a connector above the connecting rod; the supercharging device comprises a hollow hydraulic cylinder.

The temperature circulating system comprises a coil pipe and a first temperature probe for monitoring the external temperature of the anchoring unit body sample, wherein two ends of the coil pipe are connected with constant temperature water ring instruments, the coil pipe and the constant temperature water ring instruments form a circulating loop, and a fifth valve is arranged between the constant temperature water ring instruments and the coil pipe; the coil pipe is wound on the outer side of the flexible waterproof layer; and the outer wall of the sleeve is provided with a heat insulation layer.

In a further improvement, the dry-wet circulating system comprises an upper permeable stone and a lower permeable stone which are arranged in the flexible water-resisting layer; a first water content sensor is arranged on the inner side surface of the flexible waterproof layer; the lower permeable stone is communicated with a saturated water cylinder through a water inlet channel on the chassis, and a first valve is arranged between the saturated water cylinder and the chassis; the saturated water cylinder is communicated with the air compressor, and a second pressure gauge and a second pressure regulating valve are arranged between the saturated water cylinder and the air compressor; the top plate is fixedly provided with an air vent, and the air vent is provided with an air outlet hole and an air inlet hole; the air outlet is communicated with an air extractor, and a third valve is arranged between the air outlet and the air extractor; the air pump is also communicated with the lower permeable stone through a water outlet channel of the chassis, and a second valve is arranged between the air pump and the chassis; and a fourth valve is arranged on the vent pipeline of the air inlet.

Further improvement, all be provided with the silica gel piece between last permeable stone, lower permeable stone and the ground body, still be provided with foraminiferous steel sheet in the silica gel piece outside.

The section of the ventilation part is in a T shape, the outer diameter of the lower sealing circular plate is equal to that of the rock/adobe, the upper part of the ventilation part is provided with a thread which can be matched with the nut, and the bottom of the ventilation part is provided with an annular groove.

The invention also provides an anchor-soil interface performance accelerated degradation test method in an indoor artificial environment, which comprises the following steps:

the method comprises the following steps: and (3) sample installation: installing the anchoring unit body sample in the center of the pressure chamber, wrapping the periphery of the sample with a flexible waterproof layer and a rubber ring, and leading out wires of the second temperature probe and the first water content sensor from a wire outlet hole;

step two: applying confining pressure: starting the air compressor, filling the pressure chamber with water, closing the exhaust valve, and regulating and stabilizing the pressure output by the pressure chamber to the set confining pressure sigma by using the first pressure regulating valve_v；

Step three: carrying out an indoor accelerated degradation test: placing the supported anchoring unit body sample into a flexible water-resisting layer, connecting the lower end of the anchoring unit body sample with a supercharging device, connecting a displacement meter at the lower end of the anchoring unit body sample, and carrying out an indoor accelerated degradation test of the mechanical characteristics of the anchor rod interface under the simulated field environment condition according to the set confining pressure, load cycle, temperature cycle and dry-wet cycle;

step four: and (3) drawing test: and after the sample of the anchoring unit body reaches the designed test time in the indoor artificial accelerated degradation environment, the control instrument is utilized to control and load the pressurizing device, the rod body is subjected to force control loading, a drawing force P-drawing displacement s curve is measured, and the drawing force P-drawing displacement s curve is converted into an anchor-soil interface shear stress tau-shear displacement s curve.

The invention has the beneficial effects that:

1. the device has the advantages that various environmental factors are considered, the pressure chamber, the constant-temperature water ring instrument, the coil pipe, the confining pressure water cylinder, the saturated water cylinder, the supercharging device and the like are arranged, the influence of the environmental factors such as confining pressure (stratum stress), dry-wet circulation, temperature circulation, load circulation and the like on the performance of the anchor-soil interface can be effectively simulated, the field service environment of the engineering anchor rod is met, and test data are accurate and effective.

2. Utilize multiple test sensors such as controller, cooperation force sensor, first temperature probe, second temperature probe, moisture content sensor and displacement meter, regulate and control and simulate indoor artifical accelerated degradation environmental condition, whole set of test device can realize automatic control and obtain high-efficient accurate result.

3. And a heat insulation layer is added, so that the stability of temperature circulation is improved, and the test conditions can be accurately controlled.

4. The porous steel sheet and the silica gel sheet are arranged between the upper permeable stone and the lower permeable stone and between the upper surface and the lower surface of the test sample, so that the test sample can be better fixed, the loss of test sample soil particles during dry-wet circulation is effectively prevented, and the influence of the friction resistance effect of the end part of the test sample in the drawing test process on the test result is eliminated.

Drawings

FIG. 1 is a flow chart of the present invention

FIG. 2 is an indoor artificial accelerated degradation test device for mechanical properties of an anchor-soil interface of the invention

FIG. 3 is a view showing the structure of a pressure chamber according to the present invention

FIG. 4 is a schematic diagram of a sample of the anchoring interface unit according to the present invention

FIG. 5 is a view showing the connection between the top plate and the vent member according to the present invention

FIG. 6 is a three-dimensional view of a vent in accordance with the present invention

FIG. 7 is a schematic view of an engineering reference object of the present invention

FIG. 8 is a graph showing mechanical property parameters identified based on the shear tau-s curve of the anchor-soil interface

FIG. 9 shows the ultimate shear strength τ of the anchor-soil interface in an indoor accelerated degradation environment_fAccelerated degradation model

FIG. 10 shows the ultimate shear strength τ of the anchor-soil interface under the field exposure environment of the present invention_fModel of natural degeneration

FIG. 11 shows the ultimate shear strength τ of the anchor-soil interface in the field and indoor artificial acceleration environments of the present invention_fComparison of degradation curves

The number designations in the figures are:

anchoring unit body sample: 101-anchor unit body sample; 101 a-rock/adobe; 101 b-an anchor; 101 c-a rod body; 102-coating a permeable stone; 103-lower permeable stone; 104-steel sheet with holes; 105-silica gel sheet; 106-flexible water barrier; 107-rubber band.

Confining pressure system: 201-pressure chamber; 202-a chassis; 202 a-confining pressure water inlet, 202 b-pumping hole, 202 c-saturation hole and 202 d-loading through hole; 203-a sleeve; 204-a top plate; 204 a-exhaust valve; 204 b-water inlet; 204 c-water outlet; 205-a thermal insulation layer; 206-screw rod; 207-confining pressure water cylinder; 208-a vent; 208 a-outlet holes; 208 b-inlet ports; 208 c-outlet hole; 208 d-annular groove; 208 e-threads; 208 f-sealing the circular plate; 209-air compressor; 210-an upper tap; 211-lower cock; 212-a backing plate; 213-nut.

Accelerated degradation environmental simulation system: 301-reaction frame; 302-hollow hydraulic cylinder; 303-a connector; 304-a connecting rod; 305-a counter-force nut; 306-constant temperature water circulator; 307-stainless steel coil pipe; 308-air extractor; 309-saturated water cylinder; 310-a first valve; 311-a second valve; 312-a third valve; 313-a fourth valve; 314-fifth valve.

Control and test system: 401-a control instrument; 402-a displacement meter; 403-a force sensor; 404-first temperature probe; 405-a second temperature probe; 406-a first moisture content sensor; 407-a first pressure regulating valve; 408-a first pressure gauge; 409-a second pressure regulating valve; 410-second pressure gauge.

Engineering reference object: 501-filler; 502-embankment/slope; 503-earth pressure cell; 504-a second moisture content sensor; 505-temperature sensor.

Detailed Description

The embodiments of the present invention will be further described with reference to the drawings and examples. It should be noted that the examples do not limit the scope of the claimed invention.

Example 1

An anchor-soil interface performance accelerated degradation test device in an indoor artificial environment mainly comprises a confining pressure system, an accelerated degradation environment simulation system and a control and test system.

As shown in fig. 2 to 4, a stainless steel coil 307 is installed in the pressure chamber 201, and the stainless steel coil 307 is communicated with a constant temperature water circulator 306 so as to control the temperature circulation condition of the sample; the chassis 202 is provided with a confining pressure water inlet 202a, a pumping hole 202b, a saturation hole 202c and a loading through hole 202 d; the heat insulation layer 205 is arranged on the periphery of the sleeve 203 to prevent heat in the pressure chamber 201 from being dissipated; the top plate 204 is provided with a first temperature probe 404 for monitoring the temperature in the pressure chamber 201, and the top of the top plate 204 is in threaded connection with the upper screw plug 210 for sealing; a first water content sensor 406 is arranged on the periphery of the anchoring unit body sample 101 and used for monitoring the water content of the anchoring unit body sample and further calculating the saturation of the rock/adobe 101 c; the periphery of the anchoring unit body sample 101 is wrapped with a flexible waterproof layer 106 and a rubber ring 107 for sealing; the top of the anchoring unit body sample 101 is sequentially provided with a silica gel sheet 105, a steel sheet 104 with a hole, an upper permeable stone 102 and a ventilation piece 208; a second temperature probe 405 is installed in the anchoring body 101b for monitoring the temperature of the anchor-soil interface; the rod body 101c penetrates through the loading through hole 202d and the lower plug 211 to be sequentially connected with the connecting head 303, the connecting rod 304 and the counter force nut 305; a force sensor 403 is arranged between the reaction nut 305 and the hollow hydraulic cylinder 302; the displacement meter 402 is used for monitoring the drawing displacement of the rod body 101 c; the vent 208 is secured to the top of the top plate 204 by a nut 213, and a backing plate 212 is disposed between the nut 213 and the upper plug 210.

As shown in fig. 5 to 6, the section of the vent piece 208 is "T" shaped, the outer diameter of the sealing circular plate 208f at the lower part is equal to the outer diameter of the anchoring unit body sample 101, and the flexible waterproof layer 106 and the rubber ring 107 are matched to realize the sample sealing; the upper part of the ventilation piece 208 is provided with a thread 208e which can be matched with the nut 213, so that the ventilation piece can be fixed on the top plate 204, the vertical deformation of the rock/adobe 101a is constant in the acceleration test process, and the rock/adobe 101a is in a plane strain state; the bottom of the ventilation piece 208 is provided with an annular groove 208d with the depth of 2-4 mm, so that the ventilation and drying speed can be increased.

A method for developing an anchor-soil interface performance indoor accelerated degradation test by utilizing an anchor-soil interface performance accelerated degradation test device under an indoor artificial environment comprises the following steps:

s1, sample preparation. The material of the rock/adobe 101a can be undisturbed soil or rock, and undisturbed soft rock is selected in the embodiment; the height of the test sample is 100mm, the outer diameter is 200mm, and the diameter of the anchor hole is 30 mm; the grouting material can be selected from cement mortar, cement paste or resin, the cement mortar is selected in the embodiment, and the mass ratio of water, sand and ash of the cement mortar is as follows: m is_{Water (W)}：m_Sand：m_Cement0.42: 1: 1; the rod body 101c can be made of steel bars or FRP bars, and the like, and the ribbed steel bars with the diameter of 12mm are selected in the embodiment; the sample is sealed and cured 28d to ensure that the anchor 101b has sufficient strength.

And S2, mounting the sample. Installing an anchoring unit body sample 101 in the center of a pressure chamber 201, wrapping a flexible waterproof layer 106 and a rubber ring 107 on the periphery of the sample for sealing, and leading out wires of a second temperature probe 405 and a first water content sensor 406 from an outlet hole 208 c; a lower permeable stone 103, a perforated steel sheet 104 and a silica gel sheet 105 are sequentially arranged below the sample, and an upper permeable stone 102, a perforated steel sheet 104 and a silica gel sheet 105 are sequentially arranged above the sample; the rod body 101c penetrates through the lower permeable stone 103, the perforated steel sheet 104, the silica gel sheet 105 and the loading through hole 202d to be connected with the connector 303.

And S3, applying confining pressure (simulating the formation pressure). The air compressor 209 is started to fill the pressure chamber 201 with water, the exhaust valve 204a is closed, and the pressure in the pressure chamber 201 is regulated and stabilized to the set confining pressure σ by the first pressure regulating valve 407_vIn this embodiment, the confining pressure σ is set_v＝200kPa。

And S4, controlling the artificial accelerated degradation environment.

S4-1, controlling a dry-wet cycle: to the sampleWhen drying is performed, the air pump 308, the second valve 311 and the fourth valve 313 are opened, the first valve 310 and the third valve 312 are closed, moisture in the rock/adobe 101a is sucked out and evaporated, and the sample saturation S is obtained_rReach the set lower limit value S_rm-ΔS_rWhen the drying treatment is finished, the drying treatment is finished; when the sample is saturated, the second valve 311 and the fourth valve 313 are closed, the first valve 310 and the second valve 311 are opened, the pressure of the air compressor 208 is adjusted to 5-10 kPa, water in the saturated water cylinder 309 flows into the sample through the bottom of the sample, the air pump 308 is opened, the top surface of the sample is vacuumized, the saturation is accelerated, and the saturation S of the sample is to be detected_rReaches the set upper limit value S_rm+ΔS_rWhen the saturation treatment is finished, the saturation treatment is finished; in this embodiment, the average value, the amplitude value, and the period of the sample saturation level of the dry-wet cycle are set to be: 50%, 40% and 48 h.

S4-2, controlling temperature circulation: constant-temperature water in the constant-temperature water circulator 306 flows into the stainless steel coil 307 through the water inlet 204b and flows out of the water outlet 204c, so that circulating water flow is formed; setting the temperature in constant temperature water circulator 306 to an upper limit T_m+ Δ T, the temperature of the pressure chamber 201 and the sample is gradually adjusted from the average level T_mIs raised to an upper limit value T_m+ Δ T, start temperature cycling; setting the temperature T to a lower limit value T of the cycle temperature_mΔ T, set to an upper limit value T after a certain time_m+ Δ T, and holding for a certain time. In this example, the average, amplitude and period of the temperature cycle were 50 ℃,20 ℃ and 24 hours, respectively.

S4-3, load cycle control: the hollow hydraulic cylinder 302 is controlled by the controller 401 to apply a set amplitude Δ P and a set period T to the rod 101c_PThe cyclic drawing load of (2). In this embodiment, the horizontal mean, amplitude, and period of the load cycle are set to 200N, 50N, and 2s, respectively.

S5, drawing test. After the time of the test design of the anchoring unit body sample 101 in the indoor artificial accelerated degradation environment is up to 4d, the hollow hydraulic cylinder 302 is controlled by the controller 401 to load the rod body 101c in a force-controlled manner, the loading rate is 10N/s in the embodiment, and the interface shear stress tau-shear displacement s curve of the sample is measured.

A test device and method for carrying out accelerated degradation test on engineering performance of a rock-soil anchoring structure in service by utilizing anchor-soil interface performance under an indoor artificial environment comprises the following steps:

s1, investigating and analyzing field environment factors influencing mechanical properties of the rock-soil anchoring structure, wherein the field environment factors comprise characteristics such as amplitude and frequency of natural environment factors such as temperature and humidity in atmospheric environment and soil environment, and the amplitude and frequency of the natural environment factors such as temperature cycle and humidity cycle which change alternately with seasons and day and night, and characteristics such as size and action form of load environment factors (load cycle) such as traffic load, stratum stress and earthquake load;

s2, manufacturing a plurality of groups of anchoring unit body samples 101, and manufacturing 8 groups in the embodiment; after the sample is manufactured, the sample is installed in an indoor artificial accelerated degradation test device, and confining pressure is set to 200 kPa; the amplitude and frequency of the load cycle, the temperature cycle and the dry-wet cycle of the indoor artificial accelerated degradation test are all higher than the actual service condition of the rock-soil anchoring structure in service, the mean value, the amplitude and the period of the load cycle are respectively set to be 200N, 50N and 2s, the mean value, the amplitude and the period of the temperature cycle are respectively 50 ℃,20 ℃ and 24h, and the mean value, the amplitude and the period of the saturation of the sample of the dry-wet cycle are respectively as follows: 50%, 40% and 48 h; this example carried out 8 groups of samples for a time t_aIndoor accelerated degradation tests of 10d, 20d, … …, 80d, respectively.

S3 reaching set time t in indoor accelerated degradation test_aThen, the anchoring unit body sample 101 is subjected to drawing test to obtain an anchoring-soil interface shear tau-s curve, and different test times t under the indoor accelerated degradation environment are further analyzed_aThe mechanical property parameters of the anchor-soil interface, wherein, as shown in FIG. 8, the shear stiffness k₀The ultimate shear strength is the slope of the initial point of the tau-s curve_fThe peak intensity of the tau-s curve, the ultimate displacement s_fIs an ultimate shear strength τ_fCorresponding interface shear displacement, residual shear strength τ_rThe residual intensity of the τ -s curve.

S4, drawing the mechanical properties of the anchor-soil interfaceNumber (k)₀、τ_f、s_fAnd τ_r) And indoor accelerated degradation test time t_aThe relation curve is based on a regression analysis method such as a least square method, an exponential function, a rational function or a power function and the like are used as regression models, and each mechanical property parameter of the anchor-soil interface and the relation curve of the indoor accelerated degradation test time are fitted respectively to obtain regression model parameters, so that the accelerated degradation model of each mechanical property parameter of the anchor-soil interface under the indoor artificial accelerated degradation environment is established. This example is to establish the ultimate shear strength τ_fBy taking the accelerated degradation model of (1) as an example, the ultimate shear strength τ is plotted_fAnd accelerated degradation test time t_aThe relation curve, as shown in fig. 9, uses the least square method as the regression analysis method, and takes the exponential function shown in formula (1) as the regression model:

in the formula, alpha, beta and xi are undetermined regression model parameters.

For parameter tau_fAnd accelerated degradation test time t_aFitting the relation curve to obtain regression model parameters alpha-35.3, beta-0.0534 and xi-15.1, thereby establishing the anchor-soil interface ultimate shear strength tau in the indoor artificial accelerated degradation environment_fIs an accelerated degradation model of

S5, selecting a field exposure test field, wherein the field exposure test field and the serving geotechnical anchoring engineering are positioned in the same area, and ensuring that the hydrological conditions of the field exposure test field and the serving geotechnical anchoring engineering are basically the same, the soil environmental conditions are the same or the soil (rock) quality classification is the same, the deviation of the environmental temperature is not more than 5 ℃, and the deviation of the environmental humidity is not more than 10% rh; several sets of anchoring unit body samples 101, 8 sets in this example, were made and layered into the field exposure test field, thereby constructing an anchoring engineering reference, as shown in fig. 7, which is 4m deep and 6m wide in this example. In the anchoring engineering reference object, a plurality of soil pressure boxes 503, second water content sensors 504 and temperature sensors 505 are uniformly arranged along the depth direction, and are used for monitoring the load, soil water content and temperature change conditions of the site environment.

S6 setting unit preset time period delta t_bThe range of the test time t is 3-6 months, the test time t is 6 months in the embodiment, 1 group of anchoring unit body samples 101 which are pre-embedded in a field exposure test field are dug out for carrying out the drawing test, and different test time t under the field exposure environment is analyzed according to the test result_bSelecting the same regression model and regression analysis method as S4 for each mechanical property parameter of the anchor-soil interface and the field exposure test time t_bAnd fitting the relation curve to obtain regression model parameters, and establishing a natural degradation model of each mechanical property parameter of the anchor-soil interface under the field exposure environment. This example is to establish the ultimate shear strength τ_fFor example, the natural degradation model of (1) is introduced, and the parameter tau is drawn_fAnd field exposure test time t_bThe relation curve, as shown in FIG. 10, is obtained by selecting least square method as regression analysis method, and exponential function shown in formula (1) as regression model, and fitting parameter τ_fAnd field exposure test time t_bAnd fitting the relation curves to obtain regression model parameters alpha-34.9, beta-0.00273 and xi-14.3, thereby establishing the ultimate shear strength tau under the field exposure environment_fThe natural degradation model of

S7, calculating corresponding test time t when each mechanical property parameter of the anchor-soil interface degrades to the same preset value in the indoor artificial acceleration environment and the field exposure environment by using the obtained indoor accelerated degradation model and the obtained field exposure natural degradation model of each mechanical property parameter of the anchor-soil interface_aAnd t_bAs shown in fig. 11, the first degradation time similarity λ of each mechanical property parameter under the above two environments^aComprises the following steps:

λ^a＝t_b/t_a (2)

respectively calculating the average value of the first degradation time similarity relation corresponding to different preset values of each mechanical property parameter of the anchor-soil interface to obtain the degradation time similarity relation lambda of each mechanical property parameter of the anchor-soil interface in an indoor artificial acceleration environment and a field exposure environment^a＝(λ^a ₁,λ^a ₂,…,λ^a _i,…,λ^a _n)^T. This embodiment uses the parameter τ_fFirst degradation time similarity relationship under two environmentsFor example, using the indoor accelerated degradation model and the field exposure natural degradation model established in S4 and S6, tau is calculated_fT is 45kPa_aAnd t_b3.1d and 47.0d respectively, thenSimilarly, τ can be calculated_f15,20, …,40kPaAccording to the principle that the degradation time similarity relation does not change along with the time, different tau is analyzed in a statistical way_fValue is corresponded toIs 16.5, the parameter tau is obtained_fDegradation times in indoor artificially accelerated environments and in field exposure environments are similar. From this, other mechanical property parameters (k) can be calculated₀、s_fAnd τ_r) The first degradation time similarity between the field exposure environment and the indoor artificial acceleration environment.

S8, selecting the service life t_nThe geotechnical anchoring structures are located in the same area, ensure that the hydrological conditions are basically the same, the soil environmental conditions are the same or the soil (rock) quality classification is the same, the deviation of the environmental temperature is not more than 5 ℃, and the deviation of the environmental humidity is not more than 10 percent rh, and collect the existing field test dataOr carrying out the anchor rod field drawing test to obtain different ages t_nThe service life t is selected according to the drawing load P-displacement s curve of the lower anchor rod_nFor 5 years, 8 years and 10 years.

S9, establishing a first degradation time similarity relation lambda between the field exposure environment and the indoor artificial acceleration environment according to the S7^a＝(λ^a ₁,λ^a ₂,…,λ^a _i,…,λ^a _n)^TIn the interval (0.5 lambda)^a,1.5λ^a) Internally randomly generating m sample vectors lambda^d,j(j ═ 1,2, …, m), in this example, m is taken to be 100; the sample vector λ to be generated^d,j(j ═ 1,2, …, m) and the service time t of known rock-soil anchoring structures_nSubstituting λ ═ t_n/t_aWhere λ ═ λ^d,jCalculating the time t corresponding to the indoor accelerated degradation test_aWill t_aSubstituting the model into the indoor artificial environment accelerated degradation model established in S4 to obtain the current mechanical property parameter values of the anchor-soil interface of the rock-soil anchoring structure in service; in this embodiment, when j is 1, the parameter τ is_fThe calculation of (a) is described as an example, assuming that j is 1Further calculating to obtain t_n5 years later, the time corresponding to the indoor accelerated degradation testWill t_aSubstituting 100 into the accelerated degradation model under the indoor artificial environment established in S4 to obtain the current (t) of the existing rock-soil anchoring structure in service_n5 years) ultimate shear strength τ of anchor-soil interface_fAnalogously, k was obtained at 15.3kPa₀＝3412kPa/m、s_f9.2mm and t_r12.1kPa, other service life t_nAnd sample vector λ^d,jThe current anchor-soil interface mechanical property parameters of the existing rock-soil anchoring structure (j 2, …,100) can also be calculated by the method.

S10, substituting the obtained mechanical property parameter values of the current anchor-soil interface of the existing rock and soil anchoring structure into a broken line type or empirical type interface shear model, calculating the interface shear model parameters by selecting a rational and exponential type composite interface shear model shown in formula (3), and establishing the current anchor-soil interface shear model of the existing rock and soil anchoring structure:

in the formula, a, b, c and d are undetermined model parameters; n is an adjustment coefficient, and in the embodiment, n is 4.

This embodiment establishes t by using the sample vector when j equals 1_nIntroducing a current anchor-soil interface shear model of an existing rock-soil anchoring structure in 5 years as an example, calculating interface shear model parameters a to 9.8, b to 0.1, c to 12.1 and d to 0.2 according to the mechanical property parameters of the current anchor-soil interface obtained in S9, substituting the 4 model parameters into formula (3) to obtain t_nThe current anchor-soil interface shear model of the existing rock-soil anchoring structure of 5 years isThrough a load transfer method or a numerical analysis method, the load transfer method is selected in the embodiment to obtain a P-displacement s prediction curve of the drawing load of the anchor rod in the existing rock-soil anchoring structure and other service life t_nAnd sample vector λ^d,j(j ═ 2, …,100) the bolt-pull P-s curve of the geotechnical anchoring structure can also be calculated in this way; based on different service life t_nThe most accurate sample vector lambda is obtained by analyzing the principle that the joint degree of the anchor rod drawing P-s prediction curve and the actual measurement curve is optimal^d，λ^dIs the second degradation time similarity relation lambda^b。

S11, obtaining the similarity relation lambda of the second degradation time of each mechanical property parameter of the anchor-soil interface obtained by inversion^bSimilar relation lambda with first degradation time under field exposure environment and indoor artificial acceleration environment^aPerforming statistical analysis to obtain lambda^aAnd λ^bThereby obtaining the third regression of each mechanical property parameter of the corrected anchor-soil interfaceChange the time similarity relation lambda^c。

S12 similarity relation between the third degradation times^cSubstituting the model into the accelerated degradation model of each mechanical property parameter of the anchor-soil interface under the indoor artificial environment established in S4 to establish a natural degradation model of each mechanical property parameter of the anchor-soil interface of the rock-soil anchoring structure in service.