A rapid measurement device and method for gas content in quasi-saturated soil

Abstract

This invention discloses a rapid measurement device and method for quasi-saturated gas content, belonging to the field of geological engineering technology. It includes a base, a cylinder, a pressure rod, and a pad. The cylinder includes a cylinder barrel and an upper pressure cap detachably connected to the top of the cylinder barrel. The pressure rod includes an end cap and a solid cylinder located at the bottom of the end cap. The cylinder has a cylindrical cavity adapted to the solid cylinder. The pad is made of flexible material and has a ring structure. The pad is fitted onto the solid cylinder and connected to the bottom of the end cap. By designing a sealed steel container loading system as the measurement device, it ensures that soil, water, and air will not overflow from the pressure container of the device during the test of the quasi-saturated sample. Combining the characteristic stress and strain points of the stress-strain curve during the pressure process, the gas content in the quasi-saturated sample can be quickly and accurately determined. Compared with existing technologies, this invention achieves rapid measurement of quasi-saturated soil samples, and the device is easy to operate and provides high measurement accuracy.

Description

Technical Field

[0001] This invention relates to a rapid measurement device and method for gas content in quasi-saturated soil, belonging to the fields of geological engineering and technology. Background Technology

[0002] Soil is a three-phase medium composed of mineral particles forming a skeleton, with pores filled with liquid and gas. Soil whose pores are completely filled with water is generally called saturated soil. If the air content is high and the soil is connected to the atmosphere, it is called unsaturated soil. Soil containing a small amount of trapped gas in its pores is called semi-saturated soil. In aerated soils, the gas phase exists in dissolved and free gas bubble states, and the saturation degree is generally greater than 85%. Many structures along the southeastern coast of my country are built on semi-saturated soil. However, the high air pressure in the soil makes it prone to desolvation, expansion, and dissipation, making it difficult to obtain undisturbed samples of semi-saturated soil in situ for engineering projects. In recent years, due to the needs of practical engineering projects such as earthquake engineering, marine engineering, national defense engineering, and urban construction demolition, the study of the static force characteristics of semi-saturated soil has received increasing attention. The content of a small amount of trapped air in semi-saturated soil is a key factor determining the long-term stability of structures.

[0003] However, the static mechanical properties of quasi-saturated, fully saturated, and unsaturated soils differ significantly. Specifically, under unloading stress paths, the desolvation of dissolved gases in pore water and the expansion of free gases increase the compressibility of quasi-saturated soils, thus slowing down the change in pore pressure, which does not immediately decrease with decreasing total stress. Currently, the commonly used in-situ gas content testing method—empirically estimating gas content based on the propagation speed of sound waves in seabed aerated soils—is an indirect testing method with drawbacks such as large errors and lack of quantification. Most measurements of gas content in quasi-saturated soils use compression and shear tests with sealed metal devices. The volume of water expelled or inhaled during the test is assumed to be the volume of gas in the quasi-saturated soil, ignoring the volumetric deformation caused by the contraction / expansion of air bubbles in the aerated soil. This makes it impossible to accurately obtain the gas volume in transsaturated soils, and introduces significant uncertainties into the interpretation of test results, the establishment of constitutive models, and numerical analysis. Meanwhile, in researching dynamic calculation models for quasi-saturated soils both domestically and internationally—including the classic Biot two-phase medium theory, the Lekhov fluid dynamics theory neglecting the skeleton effect, and the fluid elastoplastic model considering the influence of a small amount of enclosed gas—the content of enclosed gas in the quasi-saturated soil is a crucial initial input parameter for all these models. In summary, rapidly and accurately measuring the gas content and saturation in soil and rock masses has become a key issue in studying the structural dynamic characteristics of soil and rock masses. Therefore, the problem of how to quickly and accurately determine the gas content in quasi-saturated soil urgently needs to be solved. Summary of the Invention

[0004] This invention provides a rapid measurement device and method for the gas content of saturated soil. A sealed steel container loading system is designed and manufactured as the measurement device to ensure that soil, water, and air do not overflow from the pressure vessel of the device. A pressure rod is used to apply closed loading pressure to the saturated sample in the pressure vessel. By combining the stress and strain of characteristic points in the stress-strain curve during the compression process, the gas content in the quasi-saturated sample can be quickly and accurately obtained. Compared with the prior art, this invention achieves rapid measurement of quasi-saturated samples, and the device is easy to operate and provides high accuracy in measurement results.

[0005] To achieve the above objectives, the present invention is implemented using the following technical solution.

[0006] In a first aspect, the present invention provides a rapid measuring device for gas content in quasi-saturated soil, comprising: a base, a cylinder, a pressure rod, and a pad, wherein the cylinder comprises a cylinder barrel and an upper pressure cap detachably connected to the top end of the cylinder barrel, and the bottom end of the cylinder barrel is detachably connected to the base.

[0007] The pressure rod includes an end cap and a solid cylinder located at the bottom of the end cap. The cylinder body has a cylindrical cavity adapted to the solid cylinder. The pad is made of flexible material and has an annular structure. The pad is fitted onto the solid cylinder and connected to the bottom of the end cap.

[0008] Optionally, the base has a disc-shaped structure, the top of the base has a first protrusion with a cylindrical structure, and the bottom end of the cylinder has a first groove that matches the first protrusion. The first groove is coaxially arranged with the cylindrical cavity.

[0009] Optionally, the top of the base is provided with at least three first lifting rings evenly distributed around the first protrusion, and the top of the end cap is provided with a second lifting ring.

[0010] Optionally, a first O-ring is nested on the circumferential outer wall of the first protrusion, and a second O-ring is embedded in the top of the first protrusion.

[0011] Optionally, the bottom of the upper pressure cover has a second protrusion with a cylindrical structure, and the top of the cylinder is provided with a second groove that matches the second protrusion. The second groove is coaxially arranged with the cylindrical cavity.

[0012] Optionally, the inner wall of the upper cover is embedded with a plurality of spaced-apart glyphs.

[0013] Optionally, a third O-ring is nested on the circumferential outer wall of the second protrusion, and a fourth O-ring is embedded in the bottom end of the second protrusion.

[0014] Optionally, the end cap includes an upper end portion with a disc-shaped structure and a lower end portion with a frustum-shaped structure, wherein the upper end portion, the lower end portion, and the solid cylinder are coaxially arranged.

[0015] Secondly, the present invention provides a rapid method for measuring the gas content in quasi-saturated soil, comprising:

[0016] The pre-processed rapid measurement device as described in any step of the first aspect is hoisted onto the mechanical testing machine and the quasi-saturated sample is placed into the cylinder to set up the measurement environment.

[0017] The loading device of the mechanical testing machine drives the pressure bar to perform closed loading and compression on the quasi-saturated sample in the cylinder, and records and saves the stress-strain curve of the quasi-saturated sample during the closed loading and compression process.

[0018] The volume contents of gas, water and solid particles in a unit volume of quasi-saturated sample are defined as α1, α2 and α3, respectively, and α1+α2+α3=1;

[0019] The limiting pressure p is determined based on the transition point from decreasing hardening to increasing hardening in the stress-strain curve. a ;

[0020] Based on the pressure threshold p in the stress-strain curve when the quasi-saturated soil sample is at the point of complete compaction, the stress-strain curve corresponds to this pressure threshold. f The volumetric strain ε corresponding to this pressure threshold is obtained. f ;

[0021] Based on the fluid dynamics theory of Lyakhov, p a and ε f The calculation formula for p a =20α1、 The gas content in the quasi-saturated sample was obtained.

[0022] Optionally, the establishment of the measurement environment includes:

[0023] According to the test requirements, manufacture the required size and number of bases, cylinders, pads and pressure rods, O-rings, Glyd rings, socket head cap screws and lifting eyelets;

[0024] The first protrusion on the top of the base is anchored to the first groove at the bottom of the cylinder using hexagonal bolts and O-rings.

[0025] The surface of the quasi-saturated sample was ground smooth and then placed into the cylinder.

[0026] The second protrusion at the bottom of the upper pressure cover and the second groove at the top of the cylinder are securely fastened together using hex bolts, Glyd rings, and O-rings.

[0027] Place the pad on the upper cover and align the hollow circle of the pad with the cross-section of the cavity of the upper cover;

[0028] Insert the pressure rod into the pad, the upper pressure cover and the cylindrical cavity reserved in the cylinder in sequence to discharge the gas in the cylinder;

[0029] The length of the pressure bar extending beyond the upper cover is determined by using vernier calipers, so that the end face of the pressure bar contacts the upper surface of the quasi-saturated sample;

[0030] Tighten the bolts of each layer of the measuring device and tighten and anchor the first lifting ring at the top of the base and the second lifting ring at the top of the end cap.

[0031] The measuring device is hoisted onto the mechanical testing machine using the lifting ring.

[0032] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0033] 1. By designing a rapid gas content measurement device for three-phase quasi-saturated soil, a sealed steel container loading system is used as the measurement device to ensure that soil, water and air do not overflow from the pressure vessel of the device. The quasi-saturated sample is sealed and compressed in the pressure vessel by a pressure rod. The gas content in the quasi-saturated sample is quickly and accurately obtained by combining the stress-strain curve during the compression process. Compared with traditional measurement devices, this invention effectively avoids the problems of poor sealing, complicated procedures and large errors, and improves the efficiency and accuracy of gas content measurement in three-phase quasi-saturated soil.

[0034] 2. The measuring device consists of soft rings and hard rings arranged alternately along the axial direction of the device. The axial stiffness of the cylinder is adjusted by the soft rings to match the stiffness of the soil, which effectively avoids the phenomenon of continuous accumulation of sidewall friction loss at the interface between the soil and the cylinder along the entire height of the sample.

[0035] 3. The modular assembly structure is easy to operate and practical. The use of O-rings of different sizes and multiple Gladius rings makes the connection between the various parts of the device tighter, improves the sealing of the entire device, and ensures that water and air will not overflow from the container.

[0036] 4. By setting grooves at both ends of the cylinder and setting protrusions that fit the grooves on the top of the base and the bottom of the upper cover, the contact area of ​​each component is larger and the gas overflow path is longer, which further enhances the sealing performance of the device.

[0037] 5. The pad in this invention is made of a flexible material of a certain thickness, which is used to buffer and fit the pressure bar, preventing overloading while enhancing the sealing of the device.

[0038] 6. By using the measuring device, loading device, and two condition settings, and combining the stress and strain at the characteristic points of the stress-strain curve during the test, the pressure threshold and corresponding strain can be obtained. Based on the analytical formula, the initial air content of the soil can be obtained quickly and accurately.

[0039] 7. The gas content of the three-phase quasi-saturated soil measured by this invention solves the drawback of traditional devices that can only measure the gas content change in triaxial drainage experiments but cannot determine the initial gas content of quasi-saturated soil. This provides technical support for obtaining characteristic parameters such as yield stress, compression modulus and compression index of quasi-saturated soil and determining the load on underground structures. Attached Figure Description

[0040] Figure 1 This is a front view schematic diagram of a rapid gas content measurement device for quasi-saturated soil in one embodiment of the present invention;

[0041] Figure 2 yes Figure 1 The diagram shows a side profile of the rapid gas content measurement device for quasi-saturated soil (AA direction).

[0042] Figure 3 This is a top view of the base in one embodiment of the present invention;

[0043] Figure 4 yes Figure 3 The diagram shows a side section of the base along direction AA.

[0044] Figure 5 This is a top view of the pad block in one embodiment of the present invention;

[0045] Figure 6 yes Figure 5 The diagram shows a side section of the pad block AA.

[0046] Figure 7 This is a top view of the cylinder in one embodiment of the present invention;

[0047] Figure 8 yes Figure 7 The diagram shows a side section of the cylinder barrel along direction AA.

[0048] Figure 9 This is a top view of the upper pressure cover in one embodiment of the present invention;

[0049] Figure 10 yes Figure 9 The diagram shows a side section of the upper pressure cap AA.

[0050] Figure 11 This is a top view of the pressure bar in one embodiment of the present invention;

[0051] Figure 12 yes Figure 11 The diagram shows a side section of the compression bar along direction AA.

[0052] Figure 13 This is a typical stress-strain relationship curve of quasi-saturated soil under compression in one embodiment of the present invention.

[0053] In the diagram: 1. Base; 11. First protrusion; 12. First O-ring; 13. Second O-ring; 2. Cylinder body; 21. Cylinder barrel; 211. First groove; 212. Second groove; 22. Upper pressure cap; 221. Second protrusion; 222. Glyd ring; 223. Third O-ring; 224. Fourth O-ring; 2a. Cylindrical cavity; 3. Pressure rod; 31. End cap; 311. Upper end; 312. Lower end; 32. Solid cylinder; 4. Pad; 5. First lifting ring; 6. Second lifting ring; 7. Socket head cap bolt. Detailed Implementation

[0054] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0055] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0056] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0057] Example 1

[0058] like Figure 1 and Figure 2As shown, this embodiment provides a rapid measurement device for the gas content of quasi-saturated soil, including: a base 1, a cylinder 2, a pressure rod 3, and a pad 4. The cylinder 2 includes a cylinder barrel 21 and an upper pressure cap 22 detachably connected to the top of the cylinder barrel 21, and the bottom end of the cylinder barrel 21 is detachably connected to the base 1. The pressure rod 3 includes an end cap 31 and a solid cylinder 32 located at the bottom of the end cap 31. The cylinder 2 has a cylindrical cavity 2a adapted to the solid cylinder 32. The pad 4 is made of flexible material and has a ring structure. The pad 4 is fitted onto the solid cylinder 32 and connected to the bottom of the end cap 31. By designing a sealed steel container loading system as the measurement device, it is ensured that soil, water, and air will not overflow from the pressure vessel of the device, providing an experimental environment for the rapid measurement of quasi-saturated gas content.

[0059] Example 2

[0060] Based on Example 1, this example is designed as follows.

[0061] like Figure 3 and Figure 4 As shown, the base 1 is a solid steel disc with a diameter D1 and a thickness L1. At the center of the upper end of the disc is a point with a diameter of D... 10 A cylinder with a thickness of L1 is the first protruding post 11. This structure supports the entire device, and its surface is treated to increase strength (such as heat hardening; nitrogen hardening, etc.) to improve the stability of the device.

[0062] The base 1 has four evenly distributed first lifting rings 5 ​​at its diameter D2, which facilitates the even force distribution when the device is hoisted to the mechanical testing system. The base 1 has eight hexagonal socket bolts 7 at its diameter D3, which are used to connect the cylinder 21. A second O-ring 13 is built in at the upper end L4 of the cylindrical part of the first protrusion 11 of the base 1, and a first O-ring 12 is nested at the upper port to improve the airtightness of the device when combined with the cylinder 21. The upper surface of the base 1 is treated to increase strength to ensure the sealing of the device.

[0063] like Figure 7 and Figure 8 As shown, in this embodiment, the outer periphery of the cylinder 21 is a hollow cylinder with a diameter of D4 and a height of L3. The hollow cylinder has a diameter of D6 and a height of h, which is used to hold the quasi-saturated soil sample to be tested and to serve as the track for the movement of the pressure rod 3. At the same time, the inner wall material of the cylinder 21 needs to be reinforced with increased hardness so that the measuring device can withstand higher hydrostatic pressure and provide rigid lateral confinement. Before loading the quasi-saturated sample into the cylinder 21, silicone grease is evenly applied to the inner wall of the cylinder 21 to further enhance the sealing performance of the device.

[0064] The lower end of the cylinder 21 is anchored to the base 1 by hexagonal bolts 7, and the upper end is anchored to the upper pressure cap 22 by hexagonal bolts 7. Both the upper and lower ends are provided with trapezoidal first grooves 211 and second grooves 212 at L2 to connect with other components. The first groove 211 cooperates with the first protrusion 11 to extend the gas overflow path. It is also supplemented by a Gladwell ring 222, a third O-ring 223 and a fourth O-ring 224. The third O-ring 223 is nested on the circumferential outer wall of the second protrusion 221, and the fourth O-ring 224 is embedded in the bottom end of the second protrusion 221 to further enhance the airtightness of the measuring device, prevent the leakage of soil, water and gas, and adjust the axial stiffness of the cylinder 2 to match the stiffness of the soil. This can effectively avoid the phenomenon of continuous accumulation of friction loss on the side wall at the junction of the soil and the cylinder 2 along the entire height of the sample, and reduce friction loss.

[0065] like Figure 9 and Figure 10 As shown, the upper pressure cover 22 has a diameter of D. 10 A cylinder with a thickness of L1 is provided at its lower end with a second protrusion 221, which engages with a second groove 212. A hollow cylinder with a diameter of D6 is provided through the upper cover 22, through which the pressure rod 3 can pass. It is anchored to the cylinder 21 by eight internal hex bolts 7 with a diameter of D9. The upper cover 22 and the cylinder 21 form a cylinder body 2. The hollow cylinder of the upper cover 22 and the hollow cylinder of the cylinder 21 form a cylindrical cavity 2a of the cylinder body 2. The inner wall of the upper cover 22 is reinforced with several Glyd rings 222 to enhance the friction between it and the pressure rod 3. A pad 4 is placed at the upper end to buffer and fit the pressure rod 3, preventing overloading and enhancing the sealing of the device. The pad 4 is used to seal the pressure rod 3 and the upper end face of the sample, and to fix the pressure rod 3 to prevent the pressure rod 3 from being eccentric during compression.

[0066] like Figure 5 and Figure 6 As shown, the pad 4 is a pad with an inner diameter of D. 17 The outer diameter is D7 and the thickness is L. 14 A hollow rubber disc, after the sample is loaded, with pad 4 placed on a diameter of D. 16 The pressure rod 3 is connected to the pressure rod by four symmetrically and evenly distributed internal hex bolts 7.

[0067] like Figure 11 and Figure 12 As shown, the lower end 312 of the pressure rod 3 has a diameter of D6 and a height of L. 17The solid cylinder 32 can penetrate the pad 4, the upper pressure cap 22, and the cylinder 21, and move within the pre-reserved hollow cylinders of the above three components, applying axial load to the specimen. The pressure rod 3 is relatively heavy and can stably support itself under gravity. The upper end 311 of the pressure rod 3 is an end cap 31, and the upper end 311 of the end cap 31 has a diameter D. 19 A disk with a thickness of L2, the lower end 312 of the end cap 31 has an upper and lower diameter of D respectively. 16 D7, a truncated cone with a thickness of h, is a variable cross-section that saves steel and can better transfer loads. The lower end of the truncated cone has a reserved hole for internal hexagonal bolts 7 and a pad block 4 for anchoring. The upper center of the pressure rod 3 has a second lifting ring 6 for hoisting the entire device.

[0068] In this embodiment, the entire measuring device is made of heat-treated stainless steel. The lower end face of the pressure rod 3 in contact with the specimen, the side wall of the side-limiting cylinder 21, and the upper end face of the end cap 31 of the base 1 in contact with the specimen are treated with special materials to avoid surface damage during compression. The pressure rod 3 and the inner wall of the cylinder 21 are sealed with silicone grease to further improve the airtightness of the cylinder 2.

[0069] Example 3

[0070] According to the test requirements, process the required size and number of base 1, cylinder 2, pad block 4, pressure rod 3, O-ring, Glyd ring 222, socket head cap screw 7, and lifting eye;

[0071] The first protrusion 11 on the top of the base 1 is anchored to the first groove 211 at the bottom of the cylinder 21 by an internal hex bolt 7 and an O-ring.

[0072] After the surface of the quasi-saturated sample is ground smooth, it is placed into the cylinder 21;

[0073] The second protrusion 221 at the bottom of the upper pressure cover 22 and the second groove 212 at the top of the cylinder 21 are securely fastened together by hex bolts 7, glyphs 222 and O-rings.

[0074] Place the pad 4 on the upper cover 22 and align the hollow circle of the pad 4 with the cross-section of the cavity of the upper cover 22;

[0075] Insert the pressure rod 3 into the pre-reserved cylindrical cavity of the pad 4, the upper pressure cover 22 and the cylinder 21 in sequence to allow the gas in the cylinder 21 to be discharged.

[0076] The length of the pressure rod 3 extending out of the upper pressure cover 22 is determined by using a vernier caliper, so that the end face of the pressure rod 3 contacts the upper surface of the quasi-saturated sample;

[0077] Tighten the bolts of each layer of the measuring device and tighten and anchor the first lifting ring 5 at the top of the base 1 and the second lifting ring 6 at the top of the end cap 31.

[0078] The measuring device is hoisted onto the mechanical testing machine (such as an MTS testing machine) using the lifting ring.

[0079] The loading device of the mechanical testing machine drives the pressure rod 3 to perform closed loading and compression on the quasi-saturated specimen in the cylinder 21, and records and saves the stress-strain curve of the quasi-saturated specimen during the closed loading and compression process.

[0080] The volume contents of gas, water and solid particles in a unit volume of quasi-saturated sample are defined as α1, α2 and α3, respectively, and α1+α2+α3=1;

[0081] The limiting pressure p is determined based on the transition point from decreasing hardening to increasing hardening in the stress-strain curve. a ;

[0082] Based on the pressure threshold p in the stress-strain curve when the quasi-saturated soil sample is at the point of complete compaction, the stress-strain curve corresponds to this pressure threshold. f The volumetric strain ε corresponding to this pressure threshold is obtained. f ;

[0083] Based on the fluid dynamics theory of Lyakhov, p a and ε f The calculation formula for p a =20α1、 The gas content in the quasi-saturated sample was obtained;

[0084] After the test, remove the device, remove the lifting ring, unscrew the bolts in sequence, remove the pressure rod 3 and the test soil, and clean the cylinder 21.

[0085] In this embodiment, the gas content can be rapidly measured in both quasi-saturated granular media (such as sand, soil, gravel, etc.) and quasi-conservative and continuous soil and rock media (rock, concrete, etc.).

[0086] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A rapid measuring device for gas content in quasi-saturated soil, characterized in that, include: The base (1), cylinder (2), pressure rod (3) and pad (4) are provided. The cylinder (2) includes a cylinder barrel (21) and an upper pressure cap (22) detachably connected to the top of the cylinder barrel (21). The bottom of the cylinder barrel (21) is detachably connected to the base (1). The pressure rod (3) includes an end cap (31) and a solid cylinder (32) located at the bottom of the end cap (31). The cylinder body (2) has a cylindrical cavity (2a) adapted to the solid cylinder (32). The pad (4) is made of flexible material and has an annular structure. The pad (4) is fitted on the solid cylinder (32) and connected to the bottom of the end cap (31). The base (1) has a disc-shaped structure. The top of the base (1) has a first protrusion (11) with a cylindrical structure. The bottom end of the cylinder (21) is provided with a first groove (211) that matches the first protrusion (11). The first groove (211) is coaxially arranged with the cylindrical cavity (2a). The first protrusion (11) has a first O-ring (12) nested on its circumferential outer wall, and a second O-ring (13) is embedded in the top of the first protrusion (11). The bottom of the upper pressure cover (22) has a second protrusion (221) with a cylindrical structure, and the top of the cylinder (21) is provided with a second groove (212) that matches the second protrusion (221). The second groove (212) is coaxially arranged with the cylindrical cavity (2a). The second protrusion (221) has a third O-ring (223) nested on its circumferential outer wall, and a fourth O-ring (224) is embedded in the bottom end of the second protrusion (221).

2. The rapid gas content measurement device for quasi-saturated soil according to claim 1, characterized in that, The base (1) has at least three first lifting rings (5) evenly distributed around the first protrusion (11) at its top, and the end cap (31) has a second lifting ring (6) at its top.

3. The rapid measurement device for gas content in quasi-saturated soil according to claim 1, characterized in that, The inner wall of the upper pressure cap (22) is inlaid with a plurality of spaced-apart glyphs (222).

4. The rapid measurement device for gas content in quasi-saturated soil according to claim 1, characterized in that, The end cap (31) includes an upper end (311) in the shape of a disc and a lower end (312) in the shape of a frustum, and the upper end (311), the lower end (312) and the solid cylinder (32) are coaxially arranged.

5. A rapid method for measuring the gas content in quasi-saturated soil, characterized in that, include: The pre-processed rapid measurement device as described in any one of claims 1-4 is hoisted onto the mechanical testing machine and the quasi-saturated sample is placed into the cylinder (21) to set up the measurement environment; The loading device of the mechanical testing machine drives the pressure bar (3) to perform closed loading and compression on the quasi-saturated specimen in the cylinder (21), and records and saves the stress-strain curve of the quasi-saturated specimen during the closed loading and compression process; The volume contents of gas, water, and solid particles per unit volume of a quasi-saturated sample are defined as follows: , , ,and ; The limiting pressure is determined based on the transition point from decreasing hardening to increasing hardening in the stress-strain curve. ; Based on the pressure threshold corresponding to the stress-strain curve when the quasi-saturated sample is at the point of complete compaction. The volumetric strain corresponding to this pressure threshold is obtained. ; Based on Lyakhov fluid dynamics theory and Calculation formula , The gas content in the quasi-saturated sample was obtained.

6. The rapid measurement method for gas content in quasi-saturated soil according to claim 5, characterized in that, The establishment of the measurement environment includes: According to the test requirements, the required size and number of base (1), cylinder (2), pad (4), pressure rod (3), O-ring, glyph (222), socket head cap screw (7) and lifting eye are processed; The first protrusion (11) at the top of the base (1) is anchored to the first groove (211) at the bottom of the cylinder (21) by means of an internal hex bolt (7) and an O-ring. After the surface of the quasi-saturated sample is ground smooth, it is placed into the cylinder (21); The second protrusion (221) at the bottom of the upper pressure cap (22) and the second groove (212) at the top of the cylinder (21) are tightly fastened together by an internal hex bolt (7), a glyph (222) and an O-ring; Place the pad (4) on the upper cover (22) and align the hollow circle of the pad (4) with the cross-section of the cavity of the upper cover (22); Insert the pressure rod (3) into the pre-reserved cylindrical cavity (2a) of the pad (4), the upper pressure cover (22) and the cylinder (21) in sequence to discharge the gas in the cylinder (21); The length of the pressure rod (3) extending out of the upper pressure cap (22) is determined by using a vernier caliper, so that the end face of the pressure rod (3) contacts the upper surface of the quasi-saturated sample; Tighten the bolts of each layer of the measuring device and tighten and anchor the first lifting ring (5) at the top of the base (1) and the second lifting ring (6) at the top of the end cap (31); The measuring device is hoisted onto the mechanical testing machine using the lifting ring.

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