An apparatus and method for testing the modulus of deformation attenuation of dilatant soft rock in water

Abstract

The embodiment of the present application discloses a kind of dilatant soft rock deformation modulus attenuation testing device and testing method when meeting water.The testing device, sample bearing table is set in water tank.Sample bearing table is provided with axial expansion monitoring system in both sides of axial direction.Heating component in temperature control system is set in water tank.Sound wave probe in axial sound wave monitoring system is set in both ends of sample in axial direction.The dilatant soft rock deformation modulus attenuation testing device and testing method of the embodiment of the present application can be used to test the dilatant strain and sound wave velocity of dilatant soft rock under different water temperature conditions, and establish a more ideal constitutive model, using the deformation monitoring data or sound wave data of excavation site, the strength change of dilatant soft rock can be quickly judged, which can provide more comprehensive, accurate and reliable suggestions for the stability of surrounding rock of cavern, slope stability and related supporting measures.In addition, the device is simple in structure, easy to industrialize, easy to operate and efficient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rock mechanics, in particular to a device and method for testing deformation modulus attenuation of swelling soft rock when water is encountered. BACKGROUND

[0002] Swelling soft rock is widely distributed, most of which is argillaceous cementation, and its physical and mechanical properties are significantly affected by external conditions. In particular, under the conditions of high temperature and heavy rain in the south in summer, the physical and mechanical properties will change greatly after being affected by water, resulting in argillization and softening effect, and the deformation modulus of the rock mass will decrease sharply, which has an important control effect on the stability of road slopes and chambers. Even under the condition of a relatively gentle stratum inclination, it can also produce bedding push type instability.

[0003] Currently, the mechanical attenuation of swelling soft rock when water is encountered is characterized by the ratio of compressive strength in dry and saturated states (softening coefficient). Because the compressive strength test will destroy the sample, and the rapid disintegration of mudstone after encountering water, etc., the test made by using rock samples with similar physical properties is still different from the actual situation, and the process data of mechanical attenuation when encountering water cannot be obtained. SUMMARY

[0004] In view of the deficiencies of the prior art, one aspect of the present application discloses a device for testing deformation modulus attenuation of swelling soft rock when water is encountered.

[0005] The device for testing deformation modulus attenuation of swelling soft rock when water is encountered comprises a water tank, a temperature control system, an axial expansion monitoring system, an axial acoustic wave monitoring system and a sample bearing table. The sample bearing table is arranged in the water tank. The axial expansion monitoring system is arranged on both sides of the sample bearing table in the axial direction. The heating component in the temperature control system is arranged in the water tank. The acoustic wave probe in the axial acoustic wave monitoring system is arranged at both ends of the sample in the axial direction.

[0006] According to one preferred embodiment of the present application, a fixed base is further included. The water tank is arranged on the fixed base.

[0007] According to one preferred embodiment of the present application, the temperature control system comprises a temperature control table and the heating component connected with the temperature control table.

[0008] According to a preferred embodiment of the present application, the axial expansion monitoring system comprises an electronic micrometer, a micrometer connecting rod, a vertical rod, an axial slide, a long strip plate and a disc. The electronic micrometer is arranged on the micrometer connecting rod. The micrometer connecting rod is movably connected to the vertical rod and fixed to the vertical rod by a first adjusting mechanism. The vertical rod is vertically arranged on the axial side of the sample support table. The axial slide is arranged in the water tank along the axial direction of the sample support table. The bottom of the long strip plate is slidably arranged on the axial slide. The upper part of the long strip plate is higher than the top of the water tank. The disc is movably connected to the long strip plate by a connecting member and fixed to the long strip plate by a second adjusting mechanism.

[0009] According to a preferred embodiment of the present application, the axial acoustic wave monitoring system comprises a support rod, a wire slot, a wire, a fixing ring and an ultrasonic probe. The support rod is vertically arranged. The wire slot is fixed at one end of the support rod. The wire is connected at one end to the ultrasonic probe and at the other end to an ultrasonic data processing device through the wire slot. The ultrasonic probe is arranged on the fixing ring.

[0010] According to a preferred embodiment of the present application, the sample support table comprises a supporting plate and a heat shrink tube. The supporting plate has a U-shaped structure, and the bottom of the supporting plate is fixed to the bottom of the water tank by a support and located above the axial slide. The heat shrink tube is arranged on the supporting plate. The heat shrink tube is provided with a hollow groove.

[0011] According to a preferred embodiment of the present application, the heating component is a heating rod. The heating rod is arranged in the water tank in a ring-shaped structure.

[0012] Another aspect of the present application discloses a method for testing the deformation modulus attenuation of water-swelling soft rock, which comprises the following steps:

[0013] Step (a): preparing samples, the number of which is at least 3. Measuring the height h and mass m of the samples.

[0014] Step (b): performing acoustic wave test on one of the samples in the natural water content, and then placing it in a drying oven at 105-110°C to dry to a constant weight, measuring the height h d and mass m d of the dried sample, and calculating the natural water content ω. Wherein, .

[0015] Step (c): wrapping the heat shrink tube in the expansion soft rock deformation modulus attenuation testing device according to any one of the above embodiments around the dried sample in step (b). Using a hot air blower to tightly wrap the heat shrink tube around the dried sample in step (b).

[0016] Step (d): Apply vaseline to both ends of the dried sample after step (c), and place the sample on the support plate in the dilatometer for testing the modulus of deformation of soft rock under water swelling according to any one of the preceding embodiments, and tightly attach the ultrasonic probes with the fixing ring to both ends of the sample, and make the centers of the two probes on the center axis of the sample.

[0017] Step (e): Adjust the height of the disc so that the center of the disc is on the center axis of the sample, and place the pointer of the dial gauge on the long strip in the dilatometer for testing the modulus of deformation of soft rock under water swelling according to any one of the preceding embodiments.

[0018] Step (f): Record the value of the dial gauge and measure the acoustic data of the sample by the axial acoustic monitoring system before pouring the liquid into the water tank in the dilatometer for testing the modulus of deformation of soft rock under water swelling according to any one of the preceding embodiments, and set the test temperature by the temperature control platform.

[0019] Step (g): Pour the liquid heated to the test temperature into the water tank, and make the sample below the liquid surface by 20 mm, and start recording the swelling displacement s and acoustic wave vp data, record every 2 minutes in the first hour, and then record every 10 minutes, and when the change of the displacement data measured before and after is less than 5%, it is considered that the swelling tends to be stable, and the measurement is ended.

[0020] Step (h): Draw the curves of time t and swelling displacement s, and time t and acoustic wave vp, and calculate the wave velocity attenuation amount Δvp and the corresponding swelling strain value ε of the sample, where Δvp = vp d -vp us , vp d is the wave velocity value of the dry sample, vp us is the last measured wave velocity value, , s is the swelling displacement, and h is the sample height.

[0021] Step (i): Perform deformation modulus tests on two other samples in dry and saturated states respectively, and measure the wave velocities of the samples in dry and saturated states before the shear test, and obtain the deformation modulus attenuation amount ΔES and the wave velocity attenuation amount Δvp s , where ΔES = ES d -ES s , ES d is the deformation modulus in the dry state, ES s is the deformation modulus in the saturated state, and Δvps = vp d -vp s , vp d vp is the wave velocity value of the dry sample s vp is the wave velocity value of the saturated sample

[0022] Step (k): repeating steps (a) to (i) for samples of different weathering degrees, the number of sample groups of different weathering degrees is greater than 4, and a wave velocity attenuation △vp and an expansion strain value ε curve is established by using the obtained wave velocity attenuation △vp and the corresponding sample expansion strain value ε data, and a formula △vp=Ae Bε is fitted, wherein A and B are real parameter coefficients; a wave velocity attenuation △vp and a deformation modulus attenuation △ES curve is established by using the obtained wave velocity attenuation △vp s and the corresponding deformation modulus attenuation △ES data, and a formula △T=ce s is fitted, wherein C and D are real parameter coefficients D△vps

[0023] According to a preferred embodiment of the present application, in the step (a), the sample is obtained by drilling a core by a dry drilling method. The diameter of the sample is 50-90 mm, the height is greater than or equal to the diameter, the allowable deviation of the non-parallelism of the two ends of the core is ±0.05 mm, and the allowable deviation of the perpendicularity is ±0.25°.

[0024] The expansion soft rock water-deformation modulus attenuation testing device and testing method provided by the embodiment of the present application have at least one of the following technical effects:

[0025] The expansion soft rock water-deformation modulus attenuation testing device and testing method of the embodiment of the present application use the sound wave to test the change of the expansion soft rock in the water-deformation process in a non-destructive manner, and then calculate the attenuation degree of the expansion soft rock by using the formula of the sound wave and the expansion strain and the formula of the sound wave and the rock deformation modulus. Specifically, the expansion soft rock water-deformation modulus attenuation testing device and testing method of the embodiment of the present application obtain the constitutive relationship between the rock expansion strain and the sound wave attenuation by continuously monitoring the expansion amount and the wave velocity of the expansion soft rock, and further obtain the constitutive relationship between the deformation modulus and the wave velocity in the dry and saturated states of the expansion soft rock, so as to obtain the constitutive characteristics of the expansion soft rock expansion strain and the deformation modulus attenuation. The testing device and method can quickly judge the strength attenuation of the expansion soft rock in the tunnel and slope excavation process, and further provide a reliable basis for the stability of the cavern and slope and the supporting scheme.

[0026] ​In summary, the expansion soft rock water deformation modulus attenuation testing device and testing method of the embodiment of the present application can be used for testing the expansion strain and acoustic wave velocity of the expansion soft rock under different water temperature conditions, and a more ideal constitutive model is established, the strength change of the expansion soft rock can be quickly judged by using the deformation monitoring data or acoustic wave data of the excavation site, the stability of the surrounding rock of the chamber, the stability of the slope and the related supporting measures can be more comprehensive, accurate and reliable, and the testing device of the present application has the advantages of simple structure, easy industrialization, convenient operation and high efficiency.

[0027] Some of the additional features of the present application can be explained in the following description. Some of the additional features of the present application will be apparent to those skilled in the art upon examination of the following description or upon practice of the application. The features disclosed by the present application can be realized and attained by means of the instruments, methods and combinations particularly pointed out in the following description. BRIEF DESCRIPTION OF DRAWINGS

[0028] The drawings described herein are intended to provide a further understanding of the present application, and constitute a part of the present application. The illustrative embodiments of the present application and their description serve to explain the present application. In the drawings, the same reference numbers indicate the same components. Among them,

[0029] Figure 1 It is a perspective structural schematic view of the expansion soft rock water deformation modulus attenuation testing device according to some embodiments of the present application;

[0030] Figure 2 It is a top view structural schematic view of the expansion soft rock water deformation modulus attenuation testing device according to some embodiments of the present application;

[0031] Figure 3 It is a structural schematic view of the temperature control system in the expansion soft rock water deformation modulus attenuation testing device according to some embodiments of the present application;

[0032] Figure 4 It is a top view structural schematic view of the electronic micrometer and micrometer connecting rod in the expansion soft rock water deformation modulus attenuation testing device according to some embodiments of the present application;

[0033] Figure 5 It is a front view structural schematic view of the electronic micrometer and micrometer connecting rod in the expansion soft rock water deformation modulus attenuation testing device according to some embodiments of the present application;

[0034] Figure 6 It is a side view structural schematic view of the electronic micrometer and micrometer connecting rod in the expansion soft rock water deformation modulus attenuation testing device according to some embodiments of the present application;

[0035] Figure 7 is a top view structural schematic diagram of the connection state of the axial slide, the long strip plate and the disc in the dilatant soft rock water-induced deformation modulus attenuation testing device according to some embodiments of the application;

[0036] Figure 8 is a front view structural schematic diagram of the connection state of the axial slide, the long strip plate and the disc in the dilatant soft rock water-induced deformation modulus attenuation testing device according to some embodiments of the application;

[0037] Figure 9 is a side view structural schematic diagram of the connection state of the axial slide, the long strip plate and the disc in the dilatant soft rock water-induced deformation modulus attenuation testing device according to some embodiments of the application;

[0038] Figure 10 is a top view structural schematic diagram of the axial acoustic wave monitoring system in the dilatant soft rock water-induced deformation modulus attenuation testing device according to some embodiments of the application;

[0039] Figure 11 is a front view structural schematic diagram of the axial acoustic wave monitoring system in the dilatant soft rock water-induced deformation modulus attenuation testing device according to some embodiments of the application;

[0040] Figure 12 is a side view structural schematic diagram of the axial acoustic wave monitoring system in the dilatant soft rock water-induced deformation modulus attenuation testing device according to some embodiments of the application;

[0041] Figure 13 is a three-dimensional structural schematic diagram of the sample bearing table in the dilatant soft rock water-induced deformation modulus attenuation testing device according to some embodiments of the application;

[0042] Figure 14 is a front view structural schematic diagram of the sample bearing table in the dilatant soft rock water-induced deformation modulus attenuation testing device according to some embodiments of the application;

[0043] Figure 15 is a top view structural schematic diagram of the sample bearing table in the dilatant soft rock water-induced deformation modulus attenuation testing device according to some embodiments of the application;

[0044] Figure 16 is a wave velocity-time and dilatant strain-time curve diagram in the testing method according to some embodiments of the application;

[0045] Figure 17 is a fitting curve diagram of the longitudinal wave velocity and the deformation modulus in the testing method according to some embodiments of the application. DETAILED DESCRIPTION

[0046] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the drawings in the embodiments of the present application, so that those skilled in the art can better understand the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.

[0047] It should be noted that if the terms "first", "second" and the like are used in the description and claims of the present application and the above drawings, they are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, if the terms "include" and "have" and any variations thereof are used, it is intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0048] In the present application, if the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like are used, the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0049] In addition, in addition to being used to indicate the orientation or positional relationship, the above-mentioned part of the terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For those skilled in the art, the specific meaning of these terms in the present application can be understood according to the specific circumstances.

[0050] In addition, in the present application, the terms "mounting", "setting", "provided with", "connecting", "connected", "sleeved" and the like should be understood broadly. For example, it can be fixedly connected, detachably connected, or integrally constructed; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internal communication between two devices, elements or components. For those skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific circumstances.

[0051] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0052] One aspect of an embodiment of the present invention discloses a device for testing the attenuation of the deformation modulus of swelling soft rock when exposed to water.

[0053] like Figures 1 to 15 As shown, the device for testing the attenuation of deformation modulus of expansive soft rock when exposed to water may include a water tank 2 , a temperature control system 3 , an axial expansion monitoring system 4 , an axial acoustic wave monitoring system 5 and a sample carrying platform 6 .

[0054] Furthermore, in some embodiments, a fixed base 1 may be further included. A water tank 2 is disposed on the fixed base 1 .

[0055] The sample carrier 6 is arranged in the water tank 2. Exemplarily, the sample carrier 6 includes a support plate 61 and a heat shrink tube 62. The bottom of the support plate 61 is fixed to the bottom of the water tank 2 by a bracket 63 and is located above the axial slide 44. The heat shrink tube 62 is arranged on the support plate 61. A hollow groove 621 is provided in the heat shrink tube 62. Specifically, the support plate 61 has a U-shaped structure for carrying rock samples. The heat shrink tube 62 is used to restrain the radial expansion of the rock sample. The heat shrink tube 62 has a hollow groove, which serves as a channel for the liquid to contact the rock sample.

[0056] The axial expansion monitoring system 4 is arranged on both axial sides of the sample bearing table 6. The axial expansion monitoring system 4 includes an electronic micrometer 41, a micrometer connecting rod 42, a vertical rod 43, an axial slide 44, a long strip plate 45 and a disc 46. The electronic micrometer 41 is arranged on the micrometer connecting rod 42. The micrometer connecting rod 42 is movably connected to the vertical rod 43 and fixed to the vertical rod 43 by a first adjusting mechanism. The vertical rod 43 is vertically arranged on the axial side of the sample bearing table 6. The axial slide 44 is arranged in the water tank 2 along the axial direction of the sample bearing table 6. The bottom of the long strip plate 45 is slidably arranged on the axial slide 44. The upper part of the long strip plate 45 is higher than the top of the water tank 2. The disc 46 is movably connected to the long strip plate 45 by a connecting member and fixed to the long strip plate 45 by a second adjusting mechanism. Specifically, the lower end of the vertical rod 43 is fixed to the fixed base 1. The electronic micrometer 41 is arranged on the micrometer connecting rod 42. The micrometer connecting rod 42 is movably connected to the vertical rod 43 and fixed to the vertical rod 43 by a first adjusting mechanism. The first adjusting mechanism can be a locking bolt or a locking mechanism formed by a locking bolt and a nut. The second adjusting mechanism on the disc 46 can be a locking bolt or a locking mechanism formed by a locking bolt and a nut, which is used to adjust the position of the long strip plate 45 and align the center of the disc 46 with the center of the rock core. The lower part of the long strip plate 45 is connected to the axial slide 44, and the upper part is higher than the water tank, which is used for the electronic micrometer 41 to measure the displacement. The axial slide 44 is arranged along the axial direction of the sample bearing table, and the lower part of the axial slide 44 is fixed to the water tank 2.

[0057] The ultrasonic probe 55 in the axial ultrasonic monitoring system 5 is arranged at the axial ends of the sample. The axial ultrasonic monitoring system 5 includes a support rod 51, a wire slot 52, a wire 53, a fixing ring 54 and an ultrasonic probe 55. The support rod 51 is vertically arranged. One end of the wire slot 52 is fixed to the support rod 51. One end of the wire 53 is connected to the ultrasonic probe 55, and the other end passes through the wire slot 52 and is connected to an ultrasonic data processing device. The ultrasonic probe 55 is arranged on the fixing ring 54. The wire slot 52 is used to arrange the wire 53 and prevent the wire 53 from swinging during the test to affect the test results. The fixing ring 54 is used to locate the ultrasonic probe 55 at the axial center of the rock sample.

[0058] In use, the sample is placed on the supporting plate 61, and the ultrasonic probe 55 with the fixing ring 54 is tightly attached to the two ends of the sample, so that the centers of the two probes are on the center axis of the sample. The long strip plate 45 and the disc 46 are installed on the axial slide 44, and the height of the disc 46 is adjusted so that the center of the disc 46 coincides with the center axis of the rock core and is tightly attached to the ultrasonic probe 55. The electronic micrometer 41 is erected, and the pointer of the electronic micrometer 41 is placed on the long strip plate, so that when the sample expands, the long strip plate can be pushed, and the distance of the expansion can be measured by the electronic micrometer 41.

[0059] The heating component 32 in the temperature control system 3 is arranged in the water tank 2. For example, the temperature control system 3 comprises a temperature control table 31 and a heating component 32 connected to the temperature control table 31. Specifically, the heating component 32 is a heating rod. The heating rod is arranged in the water tank 2 in a ring structure.

[0060] One aspect of the embodiment of the present application discloses a method for testing the deformation modulus attenuation of water-swelling soft rock. The method comprises the following steps:

[0061] Step (a): preparing samples, the number of which is at least 3. The height h and mass m of the samples are measured.

[0062] Step (b): performing acoustic wave test on one of the samples in the natural water content, and then placing it in a drying oven at 105-110°C to dry to constant weight. The height h and mass m of the dried sample are measured, and the natural water content ω is calculated. Wherein, d d . .

[0063] Step (c): placing the heat-shrinkable tube 62 in the deformation modulus attenuation testing device for water-swelling soft rock on the sample dried in step (b). Using a hot air blower to tightly wrap the heat-shrinkable tube 62 around the sample dried in step (b).

[0064] Step (d): applying vaseline to both ends of the sample treated in step (c), placing it on the supporting plate 61 in the deformation modulus attenuation testing device for water-swelling soft rock, tightly attaching the ultrasonic probe 55 with the fixing ring 54 in the deformation modulus attenuation testing device for water-swelling soft rock to both ends of the sample with vaseline, and making the centers of the two ultrasonic probes 55 on the central axis of the sample.

[0065] Step (e): adjusting the height of the disc 46 in the deformation modulus attenuation testing device for water-swelling soft rock to make the center of the disc 46 coincide with the axis of the sample core, and placing the pointer of the electronic micrometer 41 in the deformation modulus attenuation testing device for water-swelling soft rock on the long strip plate 45.

[0066] Step (f): recording the value of the electronic micrometer 41 before pouring liquid into the water tank 2 in the deformation modulus attenuation testing device for water-swelling soft rock, measuring the acoustic wave data of the sample through the axial acoustic wave monitoring system 5, and setting the test temperature through the temperature control table 31.

[0067] ​Step (g): Pour the liquid heated to the test temperature into the water tank 2 and make the sample at a position below the liquid surface 20 mm, and start recording the data of the swelling displacement s and the sound wave vp, recording every 2 minutes in the first hour of the sample, and recording every 10 minutes thereafter, and when the change in the displacement data measured before and after is less than 5%, it is considered that the swelling tends to be stable and the measurement is ended.

[0068] Step (h): Draw the time t and swelling displacement s curve, time t and sound wave vp curve, and calculate the wave velocity attenuation amount△vp and the corresponding sample swelling strain value ε, where△vp=vp d -vp us , vp d is the wave velocity value of the dry sample, vp us is the last measured wave velocity value, , s is the swelling displacement amount, and h is the sample height.

[0069] Step (i): Perform deformation modulus tests on two other samples in dry and saturated states respectively, and measure the wave velocities of the samples in dry and saturated states before the shear test to obtain the deformation modulus attenuation amount△ES and the wave velocity attenuation amount△vp s , where△ES=ES d -ES s , ES d is the deformation modulus in the dry state, ES s is the deformation modulus in the saturated state,△vp s =vp d -vp s , vp d is the wave velocity value of the dry sample, and vp s is the wave velocity value of the saturated sample.

[0070] Step (k): Repeat steps (a) to (i) for samples of different weathering degrees, and the number of sample groups of different weathering degrees is greater than 4, and use the obtained wave velocity attenuation amount△vp and the corresponding sample swelling strain value ε data to establish a wave velocity attenuation△vp and swelling strain value ε curve and fit the formula△vp=Ae Bε , where A and B are real parameter coefficients; use the obtained wave velocity attenuation amount△vp s and the corresponding deformation modulus attenuation amount△ES data to establish a wave velocity attenuation△vp s and deformation modulus attenuation amount△ES curve and fit the formula△T=ce D△vps , where C and D are real parameter coefficients.

[0071] Step (m): Use the two formulas in step (k) to calculate the deformation modulus attenuation of the rock mass through displacement monitoring of the excavation site cavern or slope.

[0072] Specifically, the test method for the deformation modulus attenuation of the swelling soft rock in water specifically comprises the following steps:

[0073] Step (a): In order to prevent the swelling soft rock from being disturbed and disintegrated in water, a dry drilling method is used to drill the rock core, the diameter of the rock core is preferably 50-90 mm, the height of the rock core is preferably greater than or equal to the diameter, the allowable deviation of the non-parallel degree of the two ends of the rock core is ±0.05 mm, the allowable deviation of the verticality is ±0.25°, the height h and the mass m of the measurement sample are measured, and preferably three samples are prepared for each group of samples;

[0074] Step (b): One of the samples is subjected to acoustic wave testing in the natural moisture content, and then is placed in a drying oven at 105-110°C to dry to a constant weight, the height h d and the mass m d of the dried sample are measured, and the natural moisture content is calculated; wherein h d can be used for strain calculation, strain = deformation value / original sample length, i.e. ε =△h / h a ; and can also be used for calculating wave velocity, wave velocity = distance / propagation time, vp=h a / t.

[0075] Step (c): A heat shrink tube is sleeved on the sample, a heat blower is used to make the heat shrink tube tightly wrap the sample, and a small knife is used to carve a strip-shaped hollow on the heat shrink tube to facilitate the contact between the liquid and the sample during the test;

[0076] Step (d): Vaseline is applied to the two ends of the sample, the sample is placed on a supporting plate, an acoustic wave probe with a fixing ring is tightly attached to the two ends of the sample, and the centers of the two probes are on the center axis of the sample;

[0077] Step (e): A long strip plate and a disc are installed on the axial slide, the height of the disc is adjusted so that the center of the disc coincides with the axis of the rock core, and a micrometer is erected, with the pointer of the micrometer placed on the long strip plate;

[0078] Step (f): The micrometer value is recorded before the liquid is poured, the acoustic wave data of the sample are measured, and the test temperature is set through a temperature control table (31);

[0079] Step (g): The liquid heated to the test temperature is poured into the water tank, the sample is placed at a position below the liquid surface by 20 mm, and the recording of the displacement s and the acoustic wave vp data is started, the data are recorded every 2 minutes in the first hour of the sample, and then the data are recorded every 10 minutes, and when the variation of the displacement data measured before and after is less than 5%, it is determined that the swelling tends to be stable and the sample is ended;

[0080] Step (h): Draw the curves of time t and expansion displacement s, time t and acoustic wave vp, and calculate the wave velocity attenuation △vp and the corresponding sample expansion strain value ε, where △vp=vp d -vp us , vp d is the wave velocity value of the dry sample, vp us is the last wave velocity value that can be measured (the sample is in an unsaturated state at this time), ε= , s is the expansion displacement, h is the sample height;

[0081] Step (i): The other two samples were subjected to deformation modulus tests in dry and saturated states respectively, and the wave velocity of the samples in dry and saturated states was measured before the shear test to obtain the deformation modulus attenuation △ES and wave velocity attenuation △vp s , where △ES=ES d -ES s , ES d is the deformation modulus in the dry state, ES s is the deformation modulus in saturation state, △vp s =vp d -vp s , vp d is the wave velocity value of the dry sample, vp s Wave velocity value of saturated specimen;

[0082] Step (k): Repeat steps (a) to (i) for samples with different weathering degrees. For samples with different weathering degrees, if the number of groups is greater than 4, use the obtained wave velocity attenuation △vp and the corresponding sample expansion strain value ε data to establish the wave velocity attenuation △vp and expansion strain value ε curve and fit the formula △vp=Ae Bε , where A and B are actual parameter coefficients, which can be fitted through specific test data; using the obtained wave velocity attenuation △vp s And the corresponding deformation modulus attenuation △ES data to establish the wave velocity attenuation △vp s The deformation modulus attenuation △ES curve and fitting formula △T=ce D△vps , where C and D are actual parameter coefficients, which can be fitted by specific test data;

[0083] Step (m): Using the two formulas in step k, the attenuation of the deformation modulus of the rock mass can be calculated by monitoring the displacement of the cavern or slope at the excavation site. Specifically, the calculation steps are as follows:

[0084] Use displacement monitoring equipment to monitor the deformation displacement s after excavation of the cavern or slope, and calculate the strain ε of the rock mass (ε=s / h, where h is the thickness of the rock mass that has deformed, which can be obtained using finite element numerical calculations);

[0085] The fitting formula obtained in the experiment is Δvps=Ae Bε The attenuation value of the wave velocity is converted.

[0086] The fitting formula obtained in the experiment is ΔT=ce D△vps The attenuation of the rock mass strength is converted.

[0087] The following is described in combination with specific examples.

[0088] The present example is based on the purple red swelling soft rock in Chengdu plain, and 19 groups of test samples are tested according to the test steps in the above content.

[0089] The obtained wave velocity and time, swelling strain and time curves are shown in Figure 16 .

[0090] In the present embodiment, the fitting formula of the longitudinal wave velocity and the deformation modulus is E s = 537.62e 0.0006Vp ， R² = 0.77, and the fitting curve is shown in Figure 17 .

[0091] The deformation modulus attenuation result data of each group of samples are shown in Table 1.

[0092] Table 1:

[0093]

[0094] From the above test results, it can be seen that the attenuation degree and rate of the deformation modulus of the swelling soft rock after being soaked in water can be obtained by using the device and method of the present application, and the device has simple structure and is easy to industrialize.

[0095] The swelling soft rock water deformation modulus attenuation test device and test method of the present embodiment use the acoustic wave to test the non-destructive test method to monitor the change in the swelling soft rock during the water soaking process, and then calculate the attenuation degree of the swelling soft rock through the fitting formula of the acoustic wave and the swelling strain and the acoustic wave and the rock deformation modulus. Specifically, the swelling soft rock water deformation modulus attenuation test device and test method of the present embodiment obtain the constitutive relationship of the rock swelling strain and acoustic wave attenuation through continuous monitoring of the swelling amount and wave velocity of the swelling soft rock, and further obtain the constitutive relationship of the deformation modulus and wave velocity obtained by combining the dry and saturated states of the swelling soft rock, so that the constitutive characteristics of the swelling soft rock swelling strain and deformation modulus attenuation can be obtained. The test device and method can quickly judge the strength attenuation of the swelling soft rock in the tunnel and slope excavation process, and further provide reliable basis for the stability of the cavern and slope and the supporting scheme.

[0096] In summary, the expansion soft rock water deformation modulus attenuation testing device and testing method can be used for testing the expansion strain and acoustic wave velocity of the expansion soft rock under different water temperature conditions, and an ideal constitutive model is established. The strength change of the expansion soft rock can be quickly judged by using the deformation monitoring data or acoustic wave data of the excavation site, and more comprehensive, accurate and reliable suggestions can be provided for the stability of the surrounding rock of the chamber, the stability of the slope and related supporting measures. The testing device has the advantages of simple structure, easy industrialization, convenient operation and high efficiency.

[0097] It should be noted that all features disclosed in this specification, or all steps of any method or process disclosed, can be combined in any combination, except where it is explicitly stated that a combination is not possible.

[0098] In addition, the above specific embodiments are exemplary, and those skilled in the art can think of various solutions under the inspiration of the disclosure of the present application, and these solutions also belong to the disclosed range and fall within the protection scope of the present application. Those skilled in the art should understand that the specification and drawings of the present application are illustrative and do not constitute a limitation on the claims. The protection scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for testing the attenuation of deformation modulus of swelling soft rock upon contact with water, characterized in that: A device for testing the attenuation of deformation modulus of expansive soft rock upon contact with water comprises a water tank (2), a temperature control system (3), an axial expansion monitoring system (4), an axial acoustic wave monitoring system (5), and a sample bearing platform (6); The sample carrying platform (6) is arranged in the water tank (2); The axial expansion monitoring system (4) is provided on both axial sides of the sample carrying platform (6); The heating component (32) in the temperature control system (3) is arranged in the water tank (2); The acoustic wave probes (55) in the axial acoustic wave monitoring system (5) are arranged at both axial ends of the sample; The temperature control system (3) includes a temperature control platform (31) and the heating component (32) connected to the temperature control platform (31); The axial expansion monitoring system (4) includes an electronic dial indicator (41), a dial indicator connecting rod (42), a vertical rod (43), an axial slideway (44), a long strip (45) and a disc (46); The electronic dial gauge (41) is arranged on the dial gauge connecting rod (42); The dial indicator connecting rod (42) is movably connected to the vertical rod (43) and is connected and fixed to the vertical rod (43) via a first adjustment mechanism; The vertical rod (43) is vertically arranged on the axial side of the sample supporting platform (6); The axial slideway (44) is arranged in the water tank (2) along the axial direction of the sample bearing platform (6); The bottom of the long plate (45) is slidably arranged on the axial slideway (44); the upper position of the long plate (45) is higher than the top of the water tank (2); The disc (46) is movably connected to the long plate (45) via a connecting piece, and is connected and fixed to the long plate (45) via a second adjustment mechanism; The sample carrying platform (6) includes a supporting plate (61) and a heat shrink tube (62); The support plate (61) has a U-shaped structure, and its bottom is fixed to the bottom of the water tank (2) through a bracket (63) and is located above the axial slideway (44); The heat shrink tube (62) is arranged on the supporting plate (61); a hollow groove (621) is provided in the heat shrink tube (62); It includes the following steps: Step (a): preparing at least three samples; measuring the height h and mass m of the samples; Step (b): Perform an acoustic wave test on one of the samples to determine its natural moisture content, then place it in a drying oven at 105-110°C and dry it to constant weight. Measure the height h of the dried sample. d and mass m d , and calculate the natural moisture content ω; where, ; Step (c): putting a heat shrink tube (62) on the sample dried in step (b); using a hot hair dryer to tightly wrap the heat shrink tube (62) around the sample dried in step (b); Step (d): coating both ends of the dried sample treated in step (c) with vaseline, placing the sample on a support plate (61), and placing an ultrasonic probe (55) with a fixing ring (54) close to both ends of the sample coated with vaseline, with the centers of the two ultrasonic probes (55) being located on the central axis of the sample; Step (e): adjusting the height of the disc (46) so that the center of the disc (46) coincides with the axis of the sample core; and placing the pointer of the electronic micrometer (41) on the long plate (45); Step (f): before pouring the liquid into the water tank (2), record the value of the electronic micrometer (41) and measure the acoustic wave data of the sample through the axial acoustic wave monitoring system (5), and set the test temperature through the temperature control table (31); Step (g): Pour the liquid heated to the test temperature into the water tank (2) and position the sample 20 mm below the liquid surface. Simultaneously, start recording the expansion displacement s and the acoustic wave vp data. Record the data every 2 minutes during the first hour of the test and every 10 minutes thereafter. When the difference between the displacement data before and after the measurement is less than 5%, the expansion is considered to be stable and the measurement is terminated. Step (h): Draw the curves of time t and expansion displacement s, time t and acoustic wave vp, and calculate the wave velocity attenuation △vp and the corresponding sample expansion strain value ε, where △vp=vp d -vp us , vp d is the wave velocity value of the dry sample, vp us is the last measured wave velocity value, , s is the expansion displacement, h is the sample height; Step (i): The other two samples were subjected to deformation modulus tests in dry and saturated states respectively, and the wave velocity of the samples in dry and saturated states was measured before the shear test to obtain the deformation modulus attenuation △ES and wave velocity attenuation △vp s , where △ES=ES d -ES s , ES d is the deformation modulus in the dry state, ES s is the deformation modulus in saturation state, △vp s =vp d -vp s , vp d is the wave velocity value of the dry sample, vp s Wave velocity value of saturated specimen; Step (k): Repeat steps (a) to (i) for samples with different weathering degrees. For samples with different weathering degrees, if the number of groups is greater than 4, use the obtained wave velocity attenuation △vp and the corresponding sample expansion strain value ε data to establish the wave velocity attenuation △vp and expansion strain value ε curve and fit the formula △vp=Ae Bε , where A and B are actual parameter coefficients; using the obtained wave velocity attenuation △vp s And the corresponding deformation modulus attenuation △ES data to establish the wave velocity attenuation △vp s The deformation modulus attenuation △ES curve and fitting formula △T=ce D△vps , where C and D are actual parameter coefficients; Step (m): Using the two formulas in step (k), the deformation modulus attenuation of the rock mass is estimated by monitoring the displacement of the cavern or slope at the excavation site.

2. The method for testing the attenuation of deformation modulus of swelling soft rock upon contact with water according to claim 1, characterized in that: In the step (a), the sample is obtained by drilling a core using a dry drilling method; the diameter of the core is 50-90 mm, the height is greater than or equal to the diameter, the non-parallelism deviation at both ends of the core is allowed to be ±0.05 mm, and the verticality deviation is allowed to be ±0.25°.

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