Penetration resistance indicator and method for measuring uniaxial compressive strength

Abstract

This invention provides a device for indicating penetration resistance into cement slurry and a method for measuring uniaxial compressive strength. [Solution] The penetration resistance indicator device 1 comprises a casing 11, a retractable rod 12, an elastic body 13 that biases the rod 12 to protrude, an indicator needle 15, a movement scale 16, a first flat surface 171 positioned on the surface of the cement slurry, and a second flat surface 181 having a larger base area than the first flat surface 171. The value of the movement scale 16 pointed to by the indicator needle 15, which moves due to the force received from the surface 21 of the cement slurry when the first flat surface 171 or the second flat surface 181 is pressed, is read as the magnitude of the resistance when penetrating the cement slurry. Uniaxial compressive strength is measured by inputting the reading of the penetration resistance indicator device 1 into a predetermined correlation coefficient.

Description

[Technical Field]

[0001] The present invention relates to a device for indicating the penetration resistance of a cement slurry that does not contain coarse aggregate, such as backfill injection material used in shield tunneling work for constructing tunnels, and a method for measuring uniaxial compressive strength. [Background technology]

[0002] The backfill grout used in shield tunneling requires early fixation of the segments to obtain the necessary thrust reaction force during subsequent ring excavation. Therefore, quality control checks are performed to confirm the hardening state of the material after one hour of age.

[0003] To confirm the hardening state, for example, a set of three test specimens is prepared using a cylindrical mold with an inner diameter of 5 cm and a height of 10 cm (JSCE-F506, in accordance with the Japan Society of Civil Engineers), and the uniaxial compressive strength is confirmed using a uniaxial compression testing machine.

[0004] For example, paragraph 0014 of Patent Document 1 states that the uniaxial compressive strength of the backfill injection material is 0.02 N / mm² after 1 hour of preparation. 2 The above is considered desirable. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2011-122017 [Overview of the project] [Problems that the invention aims to solve]

[0006] The quality control method using the large-scale uniaxial compression testing machine described above was complicated and time-consuming. Furthermore, in recent years, the decrease in shield tunneling projects has led to a lack of experience among shield tunneling engineers in construction management testing (e.g., uniaxial compression testing).

[0007] Furthermore, with the promotion of shorter working hours as part of work style reforms, there is a pressing need to reduce the time required for quality control. Furthermore, we focused on the ability to perform quality control quickly and easily near the tip of the tunnel where the injection actually takes place.

[0008] The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a penetration resistance indicator and a method for measuring unconfined compressive strength that can measure the unconfined compressive strength of cement slurry from its weak age immediately after manufacturing, without requiring special equipment and with a simple configuration at the construction site. [Means for solving the problem]

[0009] The invention according to claim 1 is a penetration resistance indicator device that indicates the magnitude of resistance when penetrating a cement slurry, comprising: a casing; a rod provided in the casing so as to be able to extend and retract; an elastic body provided in the casing to bias the rod so as to extend out of the casing; an indicator needle provided on the rod and facing the opening of the casing, which moves in the direction of extension and retraction of the rod; and a device provided facing the opening of the casing that indicates the amount by which the rod has moved in the retraction direction against the biasing force of the elastic body when pointed to by the indicator needle. The penetration resistance indicator comprises a displacement scale, a first planar portion located on the tip side of the rod and positioned on the surface of the cement slurry, and a second planar portion located on the tip side of the rod and positioned on the surface of the cement slurry, having a larger area than the first planar portion, wherein the value of the displacement scale pointed to by the indicator needle, which moves due to the force received from the surface of the cement slurry when the first planar portion or the second planar portion located on the tip side of the rod and positioned on the surface of the cement slurry is pressed by the cement slurry, is read as the reading.

[0010] The invention according to claim 2 is a penetration resistance indicator device according to claim 1, characterized in that the first planar portion is attached to the tip side of the rod, the pressing portion having the second planar portion has a connecting portion provided on the side opposite to the surface that is placed on the surface of the cement slurry, and the pressing portion having the first planar portion can be connected to the connecting portion.

[0011] The invention according to claim 3 is a penetration resistance indicator according to claim 1, characterized in that the area of ​​the second planar portion is less than or equal to the area of ​​the first planar portion multiplied by the ratio of the weighing capacity (maximum scale) of the movement amount scale to the scale division (minimum unit division) of the movement amount scale.

[0012] The invention according to claim 4 is a method for measuring the uniaxial compressive strength of a cement slurry from a predetermined correlation function based on the reading of a penetration resistance indicator device that indicates the magnitude of resistance when penetrated into a cement slurry, wherein the penetration resistance indicator device comprises a casing, a rod provided in the casing so as to be able to extend and retract, an elastic body provided in the casing to bias the rod so as to extend out of the casing, an indicator needle provided on the rod and facing the opening of the casing, which moves in the direction of extension and retraction of the rod, and a front The device comprises a movement scale indicating the amount by which the rod moves in the insertion direction against the biasing force of the elastic body when pointed to by an indicator needle, a first planar portion located on the tip side of the rod and positioned on the surface of the cement slurry, and a second planar portion located on the tip side of the rod and positioned on the surface of the cement slurry, having a larger area than the first planar portion, wherein when the penetration resistance indicator device is inserted by positioning the first planar portion or the second planar portion on the surface of the cement slurry, the tip side of the rod and the first planar portion or the second planar portion positioned on the surface of the cement slurry are located in the cement slurry. The value of the displacement scale pointed to by the indicator needle, which is moved by the force received from the surface of the cement slurry when pressed by the Lee, is taken as the reading and represents the magnitude of resistance when penetrating the cement slurry, and the predetermined correlation function shows the relationship between the input value determined based on the reading and the uniaxial compressive strength, and the second planar portion is placed on the tip side of the rod and on the surface of the cement slurry and penetrated, and the value of the displacement scale pointed to by the indicator needle is taken as the reading until the indicator needle points to the weighing capacity (maximum scale), and the second The ratio of the area of ​​the first planar portion to the area of ​​the flat portion is multiplied and input as the input value to the predetermined correlation function to measure the uniaxial compressive strength, the second planar portion is placed on the tip side of the rod and on the surface of the cement slurry and penetrated, and when the indicator needle points to a value greater than or equal to the measurement amount (maximum scale) of the displacement scale, the first planar portion is placed on the tip side of the rod and on the surface of the cement slurry, the first planar portion is pressed by the cement slurry, and the value of the displacement scale pointed to by the indicator needle, which has moved due to the force received from the surface of the cement slurry, is taken as the reading.This is a method for measuring uniaxial compressive strength, characterized by inputting the aforementioned reading as the input value into the predetermined correlation function to measure the uniaxial compressive strength.

[0013] The invention according to claim 5 is a method for measuring uniaxial compressive strength according to claim 4, characterized in that the predetermined correlation function is determined based on the reading when the first planar portion is placed on the tip side of the rod and on the surface of the cement slurry and the first planar portion is pressed into the cement slurry, and the uniaxial compressive strength of the cement slurry measured by a uniaxial compressive testing machine corresponding to the reading.

[0014] The invention according to claim 6 is characterized in that the predetermined correlation function shows the relationship between an input value determined based on the reading, an input value of the powder-to-water ratio determined based on the powder-to-water ratio of the cement slurry, and the unconfined compressive strength, wherein the second planar portion is placed on the tip side of the rod and on the surface of the cement slurry and penetrated, and until the indicator needle points to the weighing capacity (maximum scale) of the movement scale, the value of the movement scale pointed to by the indicator needle is taken as the reading, the reading is multiplied by the ratio of the area of ​​the second planar portion to the second planar portion as the input value, and the powder-to-water ratio of the cement slurry is taken as the input value of the powder-to-water ratio and input to the predetermined correlation function to determine the unconfined compressive strength The method for measuring unconfined compressive strength according to claim 5, characterized in that the second flat portion is placed on the tip side of the rod and on the surface of the cement slurry and penetrated, and when the indicator needle becomes greater than or equal to the weighing capacity (maximum scale) of the displacement scale, the first flat portion is placed on the tip side of the rod and on the surface of the cement slurry, the first flat portion is pressed by the cement slurry, the value of the displacement scale pointed to by the indicator needle which has moved due to the force received from the surface of the cement slurry is taken as the reading, the reading is taken as the input value, and the powder-to-water ratio of the cement slurry is input as the powder-to-water ratio input value and input to the predetermined correlation function to measure the unconfined compressive strength. [Effects of the Invention]

[0015] According to the penetration resistance indicating device of the present invention, by pressing and penetrating the first flat portion or the second flat portion disposed on the surface of the cement slurry, it is possible to indicate the magnitude of the resistance when penetrating at the value indicated by the indicating needle. By having the second flat portion with an area larger than that of the first flat portion, it is an apparatus capable of measuring in the case of a small resistance when penetrating. Therefore, at the construction site, the uniaxial compressive strength of the cement slurry can be measured from the weak material age immediately after production.

[0016] In addition, the first flat portion is attached to the tip side of the rod member, and the pressing portion having the second flat portion has a connecting portion provided on the surface opposite to the surface disposed on the surface of the cement slurry. Since the connecting portion can connect the pressing portion having the first flat portion, it is possible to uniformly press the second flat portion with a large area against the cement slurry. Also, when pulling out the entire penetration resistance indicating device including the second flat portion after penetrating it into the cement slurry, it can be pulled out integrally with the first flat portion without leaving the second flat portion in the cement slurry, and efficient measurement work can be performed.

[0017] In addition, since the area of the second flat portion is not more than the size obtained by multiplying the ratio of the scale amount (maximum scale) of the movement scale to the scale amount (minimum unit scale) of the movement scale with respect to the area of the first flat portion, it is possible to continuously measure the measurement range even when switching from the measurement using the second flat portion to the measurement using the first flat portion.

[0018] According to the uniaxial compressive strength measurement method of the present invention, even when measuring by switching between the first flat portion and the second flat portion having an area larger than that of the first flat portion while providing the same elastic body, the uniaxial compressive strength of the cement slurry can be measured.

[0019] [ Furthermore, since the predetermined correlation function is determined based on the reading when the first planar portion is placed on the tip side of the rod and on the surface of the cement slurry, and the uniaxial compressive strength measured by a uniaxial compressive testing machine of the cement slurry corresponding to the reading, the uniaxial compressive strength can be measured easily and accurately.

[0020] In addition, by determining a predetermined correlation function based on the relationship between the input reading, the input powder-water ratio, and the unconfined compressive strength, the unconfined compressive strength can be easily and accurately measured for various cement slurry formulations with varying powder-water ratios. [Brief explanation of the drawing]

[0021] [Figure 1] A penetration resistance indicator device according to the first embodiment of the present invention, in which a first planar section is arranged, with Figure 1(A) being a front view and Figure 1(B) being a bottom view. [Figure 2] The second pressing section of a penetration resistance indicator device according to the first embodiment of the present invention is shown in Figure 2(A) as a top view, Figure 2(B) as a front view, and Figure 2(C) as a bottom view. [Figure 3] A penetration resistance indicator device according to the first embodiment of the present invention, wherein a second planar section is arranged, and Figure 3(A) is a front view and Figure 3(B) is a bottom view. [Figure 4] This is an explanatory diagram of a measurement method using the first pressing part of the penetration resistance indicator device according to the first embodiment of the present invention. [Figure 5] This is an explanatory diagram of a measurement method using the first pressing part of the penetration resistance indicator device according to the first embodiment of the present invention. [Figure 6] This is an explanatory diagram of a measurement method using the second pressing section of the penetration resistance indicator device according to the first embodiment of the present invention. [Figure 7] This is an explanatory diagram of a measurement method using the second pressing section of the penetration resistance indicator device according to the first embodiment of the present invention. [Figure 8]This figure shows a correlation function illustrating the relationship between input values ​​and uniaxial compressive strength in a formulation according to the first embodiment of the present invention. [Figure 9] This is a flowchart illustrating the measurement of uniaxial compressive strength according to the first embodiment of the present invention. [Figure 10] This is an explanatory diagram illustrating the relationship between the area of ​​the first planar portion and the area of ​​the second planar portion of the penetration resistance indicator device of the present invention. [Figure 11] This figure shows a correlation function illustrating the relationship between input values ​​and uniaxial compressive strength in a formulation according to the second embodiment of the present invention. [Figure 12] This figure shows a correlation function illustrating the relationship between input values ​​and uniaxial compressive strength in a formulation according to the third embodiment of the present invention. [Figure 13] This figure shows a correlation function illustrating the relationship between input values ​​and uniaxial compressive strength in a formulation according to the fourth embodiment of the present invention. [Figure 14] This figure shows a correlation function illustrating the relationship between input values ​​and uniaxial compressive strength in a formulation according to the fifth embodiment of the present invention. [Figure 15] This figure shows a correlation function illustrating the relationship between input values ​​and uniaxial compressive strength in a formulation according to the sixth embodiment of the present invention. [Figure 16] This figure shows the correlation function between the powder water ratio and the strength coefficient according to the seventh embodiment of the present invention. [Figure 17] This figure shows the correlation function between the powder water ratio and the strength coefficient according to the eighth embodiment of the present invention. [Figure 18] The second pressing section of a penetration resistance indicator device according to the ninth embodiment of the present invention is shown in Figure 18(A) as a top view, Figure 18(B) as a front view, and Figure 18(C) as a bottom view. [Figure 19] A penetration resistance indicator device according to the ninth embodiment of the present invention, wherein a second planar portion is arranged, and Figure 19(A) is a front view and Figure 19(B) is a bottom view. [Modes for carrying out the invention]

[0022] Embodiments of the present invention will be described below with reference to the drawings. It goes without saying that the present invention is not limited to its embodiments.

[0023] [First Embodiment] The first embodiment will be described below with reference to Figures 1 to 9.

[0024] Figure 1 shows a penetration resistance indicator with the first planar section arranged, where Figure 1(A) is a front view and Figure 1(B) is a bottom view. Figure 2 shows the second pressing section of the penetration resistance indicator, where Figure 2(A) is a top view, Figure 2(B) is a front view and Figure 2(C) is a bottom view. Figure 3 shows a penetration resistance indicator with the second planar section arranged, where Figure 3(A) is a front view and Figure 3(B) is a bottom view.

[0025] Figures 4 and 5 are explanatory diagrams of the measurement method using the first pressing section of the penetration resistance indicator, Figures 6 and 7 are explanatory diagrams of the measurement method using the second pressing section of the penetration resistance indicator, Figure 8 is a diagram showing the correlation function between the input value in the mix and the uniaxial compressive strength, Figure 9 is a flowchart of the measurement of uniaxial compressive strength, and Figure 10 is an explanatory diagram of the relationship between the area of ​​the first planar section and the area of ​​the second planar section of the penetration resistance indicator.

[0026] This embodiment uses a penetration resistance indicator to measure the uniaxial compressive strength of cement slurry, which is a backfill injection material used in shield tunneling.

[0027] <Penetration resistance indicator> The penetration resistance indicator device shows the magnitude of the resistance when it penetrates the cement slurry, which is the backfill grout material. The penetration resistance indicator device is inserted into the backfill grout material after it has been manufactured.

[0028] As shown in Figures 1 to 3, the penetration resistance indicator device 1 comprises a casing 11, a rod 12, an elastic body 13, an opening 14, an indicator needle 15, a movement scale 16, a first pressing part 17, and a second pressing part 18.

[0029] The casing 11 is formed in a cylindrical shape, and a disc-shaped abutment flange 111 is provided at one end of the casing 11. A hole (not shown) is formed in the center of the abutment flange 111 for the rod 12 to protrude.

[0030] The rod member 12 is a rod-shaped component that is provided in the casing 11 so as to be able to extend and retract. The rod member 12 extends and retracts through a hole (not shown) formed in the abutment flange 111.

[0031] The elastic body 13 is located inside the casing 11 and biases the rod 12 to protrude from the hole in the abutment flange 111 of the casing 11. The elastic body 13 compresses as the rod 12 moves in the direction of retraction into the casing 11. The elastic body 13 is a spring with a predetermined spring constant, and in this embodiment, the spring constant k is k = (78.4 ± 2.0) / 40 (N / mm).

[0032] The opening 14 is provided along the direction in which the rod 12 of the casing 11 extends and retracts.

[0033] The indicator needle 15 is mounted on the rod 12 and is positioned to the outside, facing the opening 14 of the casing 11, and moves with the movement of the rod 12 in the direction of extension and retraction. The indicator needle 15 is also positioned to point to the movement amount scale 16, which will be described later.

[0034] The indicator needle 15 may be configured to stop at the position where the rod 12, which is pressed and moved after penetration begins for measurement, is most deeply embedded in the casing 11, and not move along with the rod 12 even when the rod 12 moves in the direction of returning and protruding from the casing 11.

[0035] The displacement scale 16 is positioned facing the opening 14 of the casing 11 and aligned with the direction in which the rod 12 extends and retracts. The indicator needle 15 points to the scale, which indicates the amount by which the rod 12 has moved in the retraction direction against the biasing force of the elastic body 13.

[0036] The movement scale 16 has a minimum value of 0 mm and a maximum value of 40 mm, with each division spaced 1 mm apart. In other words, the movement scale 16 has a weighing capacity of 40 mm and a division of 1 mm.

[0037] The indicator needle 15 is positioned such that when the rod 12 protrudes the furthest from the casing 11 due to the biasing force of the elastic body 13, it points to 0 mm, the smallest division of the movement scale 16, and when the rod 12 retracts the furthest into the casing 11 against the biasing force of the elastic body 13, it points to 40 mm, the largest division of the movement scale 16.

[0038] Furthermore, when the rod 12 is fully immersed in the casing 11 against the biasing force of the elastic body 13, the indicator needle 15 may be positioned to exceed 40 mm, which is the maximum scale of the movement scale 16.

[0039] In this embodiment, the amount of movement was indicated in a distance of mm, but it may also be indicated as force (for example, N) considering the spring constant of the elastic body 13, and even if it indicates force, it is included in the amount of movement scale of the present invention.

[0040] The first pressing portion 17 is attached to and fixed to the tip of the rod 12. The first pressing portion 17 is formed in a substantially frustoconical shape and includes a first flat portion 171 whose base is a circular plane.

[0041] The first planar portion 171 is located on the tip side of the rod 12 and is positioned on the surface of the specimen of the backfill injection material.

[0042] The first pressing portion 17 may be integrally formed with the tip of the rod 12.

[0043] As shown in Figure 2, the second pressing portion 18 is formed in a disc shape separate from the first pressing portion 17, and includes a top surface 180 which is a circular plane and a second flat portion 181 which is a circular plane at the bottom.

[0044] The area A2 of the second planar section 181 is larger than the area A1 of the first planar section 171. In this embodiment, the diameter of the first planar portion 171 is φ16 mm and the area A1 is 201 mm². 2 The second planar section 181 has a diameter of φ50 mm and an area A2 of 1963 mm². 2 It is set to this.

[0045] The relationship between the area A2 of the second planar section 181 and the area A1 of the first planar section 171 will be described later, but in this embodiment, the area A2 of the second planar section 181 is 1963 mm². 2 ) is the area A1 (201 mm²) of the first planar section 171. 2 This is approximately 10 times the ratio of the previous one.

[0046] As shown in Figure 3, the second pressing portion 18 is positioned on the rod 12 via the first pressing portion 17 by overlapping the upper surface 180 of the second pressing portion 18 with the bottom surface of the first pressing portion 17 which is fixed to the rod 12.

[0047] The second planar portion 181 is located on the tip side of the rod 12 and is positioned on the surface of the specimen of the backfill injection material.

[0048] By providing a second flat section 181 with a larger area than the first flat section 171, the penetration resistance indicator 1 can also indicate small resistance values ​​when it penetrates a specimen of backfill grout, allowing for easy measurement of the uniaxial compressive strength of the backfill grout at its weak age immediately after manufacturing at the construction site.

[0049] The penetration resistance indicator 1, by not having a second pressing part 18, has the first flat part 171 of the first pressing part 17, which is positioned on the tip side of the rod 12 and on the surface of the backfill injection material specimen, pressed against the specimen. The value of the movement scale 16 pointed to by the indicator needle 15, which has moved due to the force received from the surface of the specimen, is read as the magnitude of the resistance when penetrating the specimen.

[0050] Furthermore, the penetration resistance indicator device 1, by positioning the second pressing part 18, presses the second flat portion 181 of the second pressing part 18, which is positioned on the tip side of the rod 12 and on the surface of the backfill injection material specimen, against the specimen. The value of the movement scale 16 pointed to by the indicator needle 15, which has moved due to the force received from the surface of the specimen, is read as the magnitude of the resistance when penetrating the specimen.

[0051] <Outline of the method for measuring uniaxial compressive strength using a penetration resistance indicator> A penetration resistance indicator device, equipped with a first or second pressing section, is gently inserted at a constant speed into a test specimen prepared by placing the backfill material to be measured in a box-shaped container. After penetration is complete, the value indicated by the movement scale of the indicator needle is taken as the reading, and the input value is determined based on the reading and input into a predetermined correlation function to measure the uniaxial compressive strength. Note that in Figures 4 to 7, the movement scale 16 is omitted and indicated in units of 10 mm.

[0052] As shown in Figure 4, a box-shaped container (not shown) with an open top is filled with backfill material 2 to form a rectangular parallelepiped specimen 20, and measurements are taken using the first pressing section 17.

[0053] The measurer holds the casing 11 of the penetration resistance indicator device 1, which is provided with the first pressing portion 17, and positions the penetration resistance indicator device 1 vertically so that the first flat portion 171 is in contact with the upper surface 21 of the test specimen 20. In this state, the indicator needle 15 points to 0 mm, the smallest division of the displacement scale 16.

[0054] Next, as shown in Figure 5, the penetration resistance indicator 1 is slowly inserted into the surface 21 of the test specimen 20 at a constant speed.

[0055] As the first flat section 171 penetrates, the indicator needle 15 moves due to the force exerted by the specimen 20, and each movement scale 16 indicates the magnitude of the resistance when the needle penetrates the specimen 20.

[0056] After penetration is complete (for example, after the abutment flange 111 contacts the surface 21 of the specimen 20), the value of the displacement scale 16 that the indicator needle 15 finally points to is displayed as the reading S. The reading S when using the first flat section 171 is shown as S1 and represents the displacement.

[0057] Based on the reading S1, the input value SN1 is determined and input into a predetermined correlation function to measure the uniaxial compressive strength.

[0058] As shown in Figure 6, a box-shaped container (not shown) with an open top is filled with backfill material 2 to form a rectangular parallelepiped specimen 20, and measurements are taken using the second pressing section 18.

[0059] The measurer holds the casing 11 of the penetration resistance indicator device 1, which is equipped with a second pressing portion 18, and positions the penetration resistance indicator device 1 vertically so that the second flat portion 181 is in contact with the upper surface 21 of the test specimen 20. In this state, the indicator needle 15 points to 0 mm, the smallest division of the displacement scale 16.

[0060] Next, as shown in Figure 7, the penetration resistance indicator 1 is slowly inserted into the surface 21 of the test specimen 20 at a constant speed.

[0061] As the second flat section 181 penetrates, the force acting on the specimen 20 causes the indicator needle 15 to move, and each movement scale 16 indicates the magnitude of the resistance when it penetrates the specimen 20.

[0062] After penetration is complete (for example, after the second flat section 181 reaches the bottom of the container filled with the test specimen 20), the value of the displacement scale 16 that the indicator needle 15 finally points to is displayed as the reading S. The reading S when using the second flat section 181 is shown as S2 and represents the displacement.

[0063] The measurement is performed by determining the input value SN2 based on the reading value S2, inputting it into a predetermined correlation function, and calculating the uniaxial compressive strength.

[0064] <How to obtain the correlation function> The correlation function for calculating the uniaxial compressive strength by inputting the input value SN determined based on the reading value S is obtained as follows:

[0065] First, a specimen is prepared (a specimen for the penetration resistance indicator) to obtain a reading S indicating the magnitude of the resistance when the same backfill injection material with a predetermined composition is penetrated using the penetration resistance indicator 1, and a specimen is prepared (a specimen for the unconfined compression tester) to obtain the unconfined compressive strength using an unconfined compression tester (not shown).

[0066] The specimens for the penetration resistance indicator are manufactured in a rectangular parallelepiped shape as shown in Figures 4 to 7. For uniaxial compression testing, specimens are prepared, for example, in the shape of a cylinder measuring φ50mm × h100mm (in accordance with JSCE-F506, Japan Society of Civil Engineers).

[0067] For the specimens prepared for the penetration resistance indicator and the specimens for the uniaxial compression tester, measurements are performed using the penetration resistance indicator 1 and the uniaxial compression tester, respectively, at the same time intervals.

[0068] In the measurement using the penetration resistance indicator 1, the first flat portion 171 of the first pressing portion 17 is used to penetrate the specimen for the penetration resistance indicator at each time interval, and the reading S1 of the displacement scale for each time interval is obtained. This is because, since the target specimens are relatively hard and can be measured using a uniaxial compression testing machine, using the second flat portion 181 of the second pressing portion 18 may cause the reading S2 on the displacement scale to exceed the maximum value.

[0069] In measurements using a uniaxial compression testing machine, the uniaxial compression strength Qu is obtained by crushing the test specimen for the uniaxial compression testing machine at each time interval.

[0070] The vertical axis represents the uniaxial compressive strength Qu, and the horizontal axis represents the reading S1 at the first planar section 171. The corresponding uniaxial compressive strength Qu and the reading S1 at the first planar section 171 are then plotted.

[0071] Based on each plotted value, calculate a correlation function that passes through the origin. The correlation function is expressed by the following formula.

[0072] Qu = K × S (Equation 1) Here, K: Strength coefficient (the ratio indicating how much the uniaxial compressive strength Qu increases when the reading S1 on the displacement scale increases in a backfill injection material of a predetermined composition; the slope of the correlation function)

[0073] In this embodiment, the correlation function was calculated and obtained assuming it passes through the origin, but it may also be calculated assuming it has an intercept.

[0074] <Correlation function of the formulation in the backfill injection material of this embodiment> In this embodiment, correlation functions were obtained for the backfill injection materials with the formulations shown in Table 1. The backfill injection material in this embodiment is a two-component mixture type, consisting of liquid A and liquid B, and also functions as a lubricant that can be used in pipe jacking methods.

[0075] [Table 1]

[0076] The powder-to-water ratio P listed in the formulation is the weight ratio obtained by dividing the sum of the weight of cement C and the weight of non-cement powders F, which constitute the backfill grout material, by the weight of water W. That is, it is expressed as P = (C + F) / W. The water-to-powder ratio P in this embodiment is C: Hardened material weight 75kg F: Auxiliary material weight 200kg W:Water weight 895kg Therefore, The formula is P=(C+F) / W=0.307.

[0077] Uniaxial compressive strength Qu(kN / m) obtained over time using the backfill injection material of this embodiment 2Table 2 shows the reading S1 (mm) of the movement scale of the penetration resistance indicator 1 using the first flat section 171.

[0078] [Table 2]

[0079] For the values ​​obtained in Table 2, the vertical axis represents the uniaxial compressive strength Qu, and the horizontal axis represents the reading S1 at the first planar section 171, with each corresponding value being plotted.

[0080] Specifically, from 10 min to 50 min, demolding of the uniaxial compression test specimen was not possible, and therefore the uniaxial compression strength could not be obtained. Furthermore, the reading S1 using the first flat section 171 was 0 mm and could not be obtained. In addition, at 7d, the reading S1 using the first flat section 171 exceeded the maximum value of 40 mm and could not be obtained. Therefore, the data obtained at the seven points from 1h to 3d were plotted.

[0081] Figure 8 shows the correlation function calculated based on each plotted value, assuming it passes through the origin.

[0082] The correlation function is expressed by the following formula. Qu = 2.66 × S (Equation 2) Here, K: intensity coefficient (2.66) Correlation coefficient R 2 It shows a high correlation of =0.988.

[0083] <Measurement of uniaxial compressive strength using the penetration resistance indicator of this embodiment> The penetration resistance indicator 1 is inserted into the test specimen 20 to obtain a reading S, the input value N is determined from the reading S, and this is input into the correlation function shown in Equation 2 to calculate the uniaxial compressive strength Qu, thereby measuring the uniaxial compressive strength Qu.

[0084] Figure 9 illustrates, for example, the procedure for measuring uniaxial compressive strength using a penetration resistance indicator at a construction site near the tunnel tip where injection is to be performed.

[0085] Prepare a specimen 20 of the backfill injection material 2 to be measured (STEP1). The specimen 20 is formed in a rectangular parallelepiped shape by filling a box-shaped container with an open top with the backfill injection material 2 having the formulation shown in Table 1.

[0086] In the first flat portion 171, it is assumed that the reading S1 becomes 0 mm even if penetration is performed and demolding is not possible. Therefore, from immediately after production of a relatively weak material age, first, the penetration resistance indicating device 1 that arranges the second pressing portion 18 having a large area is used to penetrate the second flat portion 181 and obtain the reading S2 (STEP2 to STEP4).

[0087] Determine whether the reading S2 is less than 40 mm, which is the scale amount (maximum scale) of the movement scale 16 (STEP5). As the curing of the specimen 20 progresses over time, the reading S2 indicated by the indicating needle 15 when penetrating the second flat portion 181 increases. However, when the indicating needle 15 points to 40 mm, which is the scale amount (maximum scale) of the movement scale 16, the measurement by the second flat portion 181 reaches its limit.

[0088] If the determination in STEP5 is YES, determine the input value SN2 based on the obtained reading S2 (STEP6). Multiply the obtained reading S2 by the ratio α of the area A1 of the first flat portion 171 to the area A2 of the second flat portion 181 (in this embodiment, the area A1 (201 mm 2 ), the area A2 (1963 mm 2 ), and α = 0.1) and determine it as the input value SN2.

[0089] Input the determined input value SN2 into a predetermined correlation function (Equation 2) to calculate the uniaxial compressive strength Qu and use it as the measured value (STEP7).

[0090] Determine whether measurement at the next time point is necessary (STEP8). This determination is, for example, when the allowable uniaxial compressive strength has already been obtained (uniaxial compressive strength 0.02 N / mm at 1 hour after the production of the working fluid 2The above is the acceptable standard, which is 0.02 N / mm² over a period of 30 minutes. 2 You may also make a decision based on the following: (If the above has already been confirmed)

[0091] If the result of STEP 8 is Yes, return to the beginning of STEP 2 and perform the measurement at the next time interval in the same manner. If the result of STEP 8 is No, end the measurement.

[0092] If the determination in STEP 5 is No, the penetration resistance indicator 1 equipped with a smaller area first pressing part 17 is used to penetrate the first flat part 171 without using the second pressing part 18, and the reading S1 is obtained (STEP 9 to STEP 11).

[0093] The input value SN1 is determined based on the acquired reading S1 (STEP 12). The reading S1 of the displacement scale 16 pointed to by the indicator needle 15 when the first flat portion 171 is inserted into the test specimen 20 is determined as the input value SN1.

[0094] The determined input value SN1 is input into a predetermined correlation function (Equation 2) to calculate the uniaxial compressive strength Qu, which is then used as the measured value (STEP 13).

[0095] Determine whether further measurements are necessary (STEP 14). This decision is the same as in STEP 8.

[0096] If the result of STEP 14 is Yes, return to the beginning of STEP 9 and perform the measurement at the next time interval in the same manner. If the result of STEP 14 is No, end the measurement.

[0097] Specifically, until the indicator needle 15 points to the weighing capacity (maximum scale) of the movement scale 16, measurement is performed by penetration of the second flat section 181. Once the indicator needle 15 points to the weighing capacity (maximum scale) of the movement scale 16, measurement is performed by penetration of the first flat section 171 to measure the uniaxial compressive strength Qu. Then, the next measurement over time is repeated.

[0098] Table 3 shows the results of obtaining the uniaxial compressive strength Qu by determining the input value SN2 from the reading S2 obtained by penetrating the specimen 20 of the backfill injection material 2 with the formulation shown in Table 1 using the penetration resistance indicator 1 to which the indicator needle 15 points to the weighing capacity (maximum scale) of the displacement scale 16, which is 40 mm, starting from 10 min after immediately after manufacture, and inputting it into the correlation function of Equation 2 to obtain the uniaxial compressive strength Qu.

[0099] [Table 3]

[0100] <Relationship between the area of ​​the first planar section and the area of ​​the second planar section> As shown in Figure 10, the operator first measures the reading S2 on the second flat section 181 immediately after manufacturing until the reading S2 reaches the weighing capacity (maximum scale) of the movement scale 16, which is 40 mm (Figure 10(A)). If it exceeds this, the operator switches to the first flat section 171 to continue measuring (Figure 10(B)). It is important to set the relationship between the area of ​​the first flat section and the area of ​​the second flat section so that the reading S1 can be read immediately after switching, that is, so that the movement of the indicator needle 15 can be recognized (for example, the movement scale 16 moves from its minimum value of 0 mm to at least the minimum unit scale (1 mm) which is the scale division).

[0101] Spring constant of elastic body 13: k The reading when the indicator needle 15 points to the movement scale 16: S The indicator needle 15 points to the weighing capacity (maximum scale) of the movement scale 16. Reading: Smax (40mm on the actual machine) The reading when the indicator needle 15 points to the division (smallest unit division) of the movement scale 16: Smin (interval from the minimum division 0mm to the first division: 1mm on the actual machine) Area of ​​the first planar section 171: A1 Area of ​​the second planar section 181: A2 Pressure from the specimen onto the first flat section 171 during penetration: P1 Pressure from the specimen onto the second flat section 181 during penetration: P2

[0102] Assume that the force F1 acting on the elastic body 13 when the indicator needle 15 is at a reading Smin, which points to the division (smallest unit division) of the movement scale 16 during penetration in the first flat section 171, and the force F2 acting on the elastic body 13 when the indicator needle 15 is at a reading Smax, which points to the weighing capacity (maximum division) of the movement scale 16 during penetration in the second flat section 181, are balanced.

[0103] F1 = F2...(1) Here, F1 = P1 × A1 = k × Smin ... (2) F2 = P2 × A2 = k × Smax ... (3)

[0104] (3)÷(2) (P2 × A2) / (P1 × A1) = (k × Smax) / (k × Smin) ... (4)

[0105] When switching between the second planar section 181 and the first planar section 171, the test specimen 20 is in the same state, P1=P2=P···(5)

[0106] Substitute (5) into (4) (P × A²) / (P × A¹) = (k × Smax) / (k × Smin)

[0107] A2 = A1 × Smax / Smin This is the result.

[0108] The area A2 of the second planar section 181 can be expressed as the area A1 of the first planar section 171 multiplied by the ratio of the weighing capacity (maximum scale) of the movement scale 16 to the scale division (minimum unit division) of the movement scale 16.

[0109] These represent the limit values ​​of the area ratio. Expressed as a range, if the area A2 of the second planar section 181 is set to be less than or equal to the area A1 of the first planar section 171 multiplied by the ratio of the weighing capacity (maximum scale) of the movement scale 16 to the scale division (minimum unit division) of the movement scale 16, then the reading S1 can be read immediately when switching from the second planar section 181 to the first planar section 171, that is, the movement of the indicator needle 15 can be recognized.

[0110] Specifically, the division (minimum unit division) of the movement scale 16 is 1 mm, and the weighing capacity (maximum division) of the movement scale 16 is 40 mm. Therefore, the ratio of the weighing capacity (maximum division) of the movement scale 16 to the division (minimum unit division) of the movement scale 16 is 40 times. Thus, the area A2 of the second planar section 181 should be set to be 40 times or less the area A1 of the first planar section 171.

[0111] In this embodiment, the area A2 of the second planar portion 181 is 1963 mm². 2 Therefore, the area A1 of the first planar section 171 is 201 mm². 2 The ratio is approximately 10 times, and when switching from the second flat section 181 to the first flat section 171, the reading S1 is set to be approximately 4 times the scale division, i.e., approximately 4 mm.

[0112] To put this in terms of the first planar section 171, the area A1 of the first planar section 171 is set to be at least the size obtained by multiplying the area A2 of the second planar section 181 by the ratio of the scale division (smallest unit division) of the movement scale 16 to the weighing capacity (maximum division) of the movement scale 16.

[0113] According to the penetration resistance indicator device 1 of this embodiment, by pressing and penetrating the first flat portion 171 or the second flat portion 181 placed on the surface 21 of the backfill injection material 2, which is cement slurry, the magnitude of the resistance at the time of penetration can be indicated by the value pointed to by the indicator needle 15. By having the second flat portion 181 which has a larger area than the first flat portion 171, the device is capable of measuring even small resistances at the time of penetration. Therefore, the uniaxial compressive strength Qu of the backfill injection material 2 can be measured at the construction site from its weak age immediately after manufacture.

[0114] In addition, since the area A2 of the second planar section 181 is less than or equal to the area A1 of the first planar section 171 multiplied by the ratio of the weighing capacity (maximum scale) of the movement scale 16 to the scale division (minimum unit scale) of the movement scale 16, it is possible to continuously measure the measurement range even when switching from measurement using the second planar section 181 to measurement using the first planar section 171.

[0115] According to the uniaxial compressive strength measurement method of this embodiment, even when the same elastic body is used and measurements are taken by switching between the first planar portion 171 and the second planar portion 181 which has a larger area than the first planar portion 171, the uniaxial compressive strength Qu of the backfill injection material 2 can be measured continuously.

[0116] In addition, since the predetermined correlation function is determined based on the reading S1 when the first flat portion 171 is placed on the tip side of the rod 12 and on the surface 21 of the backfill injection material 2 and pressed against the backfill injection material 2, and the uniaxial compressive strength Qu measured by a uniaxial compression testing machine corresponding to the reading S1, the uniaxial compressive strength Qu can be measured easily and accurately.

[0117] [Second Embodiment] A second embodiment of the present invention will be described with reference to Figure 11, etc. Note that the same parts as in the first embodiment will be omitted from the explanation, and the following will mainly describe the differences.

[0118] The second embodiment differs from the first embodiment only in the composition of the backfill material 2 to be measured. The backfill material 2 in the second embodiment is a non-air-based backfill material, and its composition is shown in Table 4.

[0119] [Table 4]

[0120] The powder-to-water ratio P of the backfill injection material 2 in this embodiment is C: Hardened material weight 230kg F: Auxiliary material weight 30kg W:Water weight 864kg Therefore, The formula is P=(C+F) / W=0.301.

[0121] Uniaxial compressive strength Qu(kN / m) obtained over time using the backfill injection material of this embodiment 2 Table 5 shows the reading S1 (mm) of the movement scale of the penetration resistance indicator 1 using the first flat section 171.

[0122] [Table 5]

[0123] For the values ​​obtained in Table 5, the vertical axis represents the uniaxial compressive strength Qu, and the horizontal axis represents the reading S1 at the first planar section 171, with each corresponding value being plotted.

[0124] Specifically, from 10 min to 30 min, demolding of the uniaxial compression test specimen was not possible, and therefore the uniaxial compression strength could not be obtained. Also, at 6 h, the reading S1 using the first flat section 171 exceeded the maximum value of 40 mm and could not be obtained. Therefore, the data obtained at 10 points from 35 min to 3 h were plotted.

[0125] Figure 11 shows the correlation function calculated based on each plotted value, assuming it passes through the origin.

[0126] The correlation function is expressed by the following formula. Qu = 2.66 × S (Equation 3) Here, K: intensity coefficient (2.66) Correlation coefficient R 2 It shows a high correlation of =0.990.

[0127] Table 6 shows the results of obtaining the uniaxial compressive strength Qu by determining the input value SN2 from the reading S2 obtained by penetrating the specimen 20 of the backfill injection material 2 with the formulation shown in Table 4 using the penetration resistance indicator 1 to which the second flat section 181 is attached, from 10 min after manufacturing until the indicator needle 15 points to the weighing capacity (maximum scale) of the displacement scale 16, which is 40 mm, and inputting it into the correlation function of Equation 3.

[0128] [Table 6]

[0129] [Third Embodiment] A third embodiment of the present invention will be described with reference to Figure 12, etc. Note that the same parts as in the first and second embodiments will be omitted from the explanation, and the following will mainly describe the parts that differ.

[0130] The third embodiment differs from the first and second embodiments only in the composition of the backfill material 2 to be measured. The backfill material 2 in the third embodiment is a backfill material containing 15% air, and its composition is shown in Table 7.

[0131] [Table 7]

[0132] The powder-to-water ratio P of the backfill injection material 2 in this embodiment is C: Hardened material weight 230kg F: Auxiliary material weight 30kg W:Water weight 720kg Therefore, The formula is P=(C+F) / W=0.361.

[0133] Uniaxial compressive strength Qu(kN / m) obtained over time using the backfill injection material of this embodiment 2 Table 8 shows the reading S1 (mm) of the movement scale of the penetration resistance indicator 1 using the first flat section 171.

[0134] [Table 8]

[0135] For the values ​​obtained in Table 8, the vertical axis represents the uniaxial compressive strength Qu, and the horizontal axis represents the reading S1 at the first planar section 171, with each corresponding value being plotted.

[0136] Specifically, from 10 min to 25 min, demolding of the uniaxial compression test specimen was not possible, and therefore the uniaxial compression strength could not be obtained. Also, at 3.0 h, the reading S1 using the first flat section 171 could not be obtained because it exceeded the maximum value of 40 mm. Therefore, the data obtained at 11 points from 30 min to 2.5 h were plotted.

[0137] Figure 12 shows the correlation function calculated based on each plotted value, assuming it passes through the origin.

[0138] The correlation function is expressed by the following formula. Qu = 3.02 × S (Equation 4) Here, K: intensity coefficient (3.02) Correlation coefficient R 2 It shows a high correlation of =0.994.

[0139] Table 9 shows the results of obtaining the uniaxial compressive strength Qu by determining the input value SN2 from the reading S2 obtained by penetrating the specimen 20 of the backfill injection material 2 with the formulation shown in Table 7 using the penetration resistance indicator 1 fitted with the second flat section 181, from 10 min after manufacturing until the indicator needle 15 pointed to the weighing capacity (maximum scale) of the displacement scale 16, which is 40 mm, and inputting this into the correlation function of Equation 4.

[0140] [Table 9]

[0141] [Fourth Embodiment] A fourth embodiment of the present invention will be described with reference to Figure 13, etc. Note that the same parts as in the first to third embodiments will be omitted from the explanation, and the following will mainly describe the parts that differ.

[0142] The fourth embodiment differs from the first to third embodiments only in the composition of the backfill material 2 to be measured. The backfill material 2 in the fourth embodiment is a backfill material containing 24% air, and its composition is shown in Table 10.

[0143] [Table 10]

[0144] The powder-to-water ratio P of the backfill injection material 2 in this embodiment is C: Hardened material weight 230kg F: Auxiliary material weight 30kg W:Water weight 635kg Therefore, The formula is P=(C+F) / W=0.409.

[0145] Uniaxial compressive strength Qu(kN / m) obtained over time using the backfill injection material of this embodiment 2 Table 11 shows the reading S1 (mm) of the movement scale of the penetration resistance indicator 1 using the first flat section 171.

[0146] [Table 11]

[0147] For the values ​​obtained in Table 11, the vertical axis represents the uniaxial compressive strength Qu, and the horizontal axis represents the reading S1 at the first planar section 171, with each corresponding value being plotted.

[0148] Specifically, from 10 min to 25 min, demolding of the uniaxial compression test specimen was not possible, and therefore the uniaxial compression strength could not be obtained. Also, at 6 h, the reading S1 using the first flat section 171 exceeded the maximum value of 40 mm and could not be obtained. Therefore, the data obtained at 11 points from 30 min to 3 h were plotted.

[0149] Figure 13 shows the correlation function calculated based on each plotted value, assuming it passes through the origin.

[0150] The correlation function is expressed by the following formula. Qu = 3.07 × S (Equation 5) Here, K: intensity coefficient (3.07) Correlation coefficient R 2 It shows a high correlation of =0.984.

[0151] Table 12 shows the results of obtaining the uniaxial compressive strength Qu by determining the input value SN2 from the reading S2 obtained by penetrating the specimen 20 of the backfill injection material 2 with the formulation shown in Table 10 using the penetration resistance indicator 1 to which the indicator needle 15 points to the weighing capacity (maximum scale) of the displacement scale 16, which is 40 mm, starting from 10 min after manufacturing, and inputting it into the correlation function of Equation 5 to obtain the uniaxial compressive strength Qu.

[0152] [Table 12]

[0153] [Fifth Embodiment] A fifth embodiment of the present invention will be described with reference to Figure 14, etc. Note that the same parts as in the first to fourth embodiments will be omitted from the explanation, and the following will mainly describe the parts that differ.

[0154] The fifth embodiment differs from the first to fourth embodiments only in the composition of the backfill material 2 to be measured. The backfill material 2 in the fifth embodiment is a backfill material containing 30% air, and its composition is shown in Table 13.

[0155] [Table 13]

[0156] The powder-to-water ratio P of the backfill injection material 2 in this embodiment is C: Hardened material weight 230kg F: Auxiliary material weight 30kg W:Water weight 578kg Therefore, The formula is P=(C+F) / W=0.450.

[0157] Uniaxial compressive strength Qu(kN / m) obtained over time using the backfill injection material of this embodiment 2 Table 14 shows the reading S1 (mm) of the movement scale of the penetration resistance indicator 1 using the first flat section 171.

[0158] [Table 14]

[0159] For the values ​​obtained in Table 14, the vertical axis represents the uniaxial compressive strength Qu, and the horizontal axis represents the reading S1 at the first planar section 171, with each corresponding value being plotted.

[0160] Specifically, from 10 min to 25 min, demolding of the uniaxial compression test specimen was not possible, and therefore the uniaxial compression strength could not be obtained. Also, at 3 h, the reading S1 using the first flat section 171 exceeded the maximum value of 40 mm and could not be obtained. Therefore, the data obtained at 10 points from 30 min to 2 h were plotted.

[0161] Figure 14 shows the correlation function calculated based on each plotted value, assuming it passes through the origin.

[0162] The correlation function is expressed by the following formula. Qu = 3.15 × S (Equation 6) Here, K: intensity coefficient (3.15) Correlation coefficient R 2 It shows a high correlation of =0.995.

[0163] Table 15 shows the results of obtaining the uniaxial compressive strength Qu by determining the input value SN2 from the reading S2 obtained by penetrating the specimen 20 of the backfill injection material 2 with the formulation shown in Table 13 using the penetration resistance indicator 1 to which the indicator needle 15 points to the weighing capacity (maximum scale) of the displacement scale 16, which is 40 mm, starting from 10 min after manufacturing, and inputting it into the correlation function of Equation 6 to obtain the uniaxial compressive strength Qu.

[0164] [Table 15]

[0165] [Sixth Embodiment] A sixth embodiment of the present invention will be described with reference to Figure 15, etc. Note that the same parts as in the first to fifth embodiments will be omitted from the explanation, and the following will mainly describe the parts that differ.

[0166] The sixth embodiment differs from the first to fifth embodiments only in the composition of the backfill material 2 to be measured. The backfill material 2 in the sixth embodiment is a backfill material containing 35% air, and its composition is shown in Table 16.

[0167] [Table 16]

[0168] The powder-to-water ratio P of the backfill injection material 2 in this embodiment is C: Hardened material weight 230kg F: Auxiliary material weight 30kg W:Water weight 530kg Therefore, The formula is P=(C+F) / W=0.491.

[0169] Uniaxial compressive strength Qu(kN / m) obtained over time using the backfill injection material of this embodiment 2 Table 17 shows the reading S1 (mm) of the movement scale of the penetration resistance indicator 1 using the first flat section 171.

[0170] [Table 17]

[0171] For the values ​​obtained in Table 17, the vertical axis represents the uniaxial compressive strength Qu, and the horizontal axis represents the reading S1 at the first planar section 171, with each corresponding value being plotted.

[0172] Specifically, from 10 min to 25 min, demolding of the uniaxial compression test specimen was not possible, and therefore the uniaxial compression strength could not be obtained. Also, at 6 h, the reading S1 using the first flat section 171 exceeded the maximum value of 40 mm and could not be obtained. Therefore, the data obtained at 13 points from 30 min to 5 h were plotted.

[0173] Figure 15 shows the correlation function calculated based on each plotted value, assuming it passes through the origin.

[0174] The correlation function is expressed by the following formula. Qu = 3.48 × S (Equation 7) Here, K: intensity coefficient (3.48) Correlation coefficient R 2 It shows a high correlation of =0.988.

[0175] Table 18 shows the results of obtaining the uniaxial compressive strength Qu by determining the input value SN2 from the reading S2 obtained by penetrating the specimen 20 of the backfill injection material 2 with the formulation shown in Table 16 using the penetration resistance indicator 1 to which the indicator needle 15 points to the weighing capacity (maximum scale) of the displacement scale 16, which is 40 mm, starting from 10 min after manufacturing, and inputting it into the correlation function of Equation 7 to obtain the uniaxial compressive strength Qu.

[0176] [Table 18]

[0177] [Seventh Embodiment] A seventh embodiment of the present invention will be described with reference to Figure 16, etc. Note that the same parts as in the first to sixth embodiments will be omitted from the explanation, and the following will mainly describe the parts that differ.

[0178] The seventh embodiment measures the uniaxial compressive strength Qu by correcting the correlation function based on the powder-to-water ratio P of the mixture of the backfill injection material 2, which is known in advance.

[0179] Table 19 shows the relationship between the powder-to-water ratio P and the strength coefficient K of the backfill injection material 2 according to the first to sixth embodiments. It can be seen that the strength coefficient K increases as the powder-to-water ratio P increases.

[0180] [Table 19]

[0181] For the values ​​in Table 19, the vertical axis was plotted with the intensity coefficient K, and the horizontal axis with the powder-to-water ratio P, and the six corresponding data points were plotted.

[0182] Figure 16 shows the correlation function between the powder water ratio P and the intensity coefficient K, calculated based on each plotted value.

[0183] The correlation function between the water-to-powder ratio P and the intensity coefficient K is expressed by the following equation. K=3.94×P+1.49 (Formula 8) Correlation coefficient R 2 It shows a high correlation of =0.938.

[0184] <Calculation of a correlation function to estimate uniaxial compressive strength from powder water ratio and readings> A correlation function is calculated to estimate the uniaxial compressive strength Qu from the powder water ratio P and the reading S1 of the displacement scale 16 obtained by penetrating the first flat section 171. That is, the correlation function (Equation 9) is calculated by substituting the correlation function (Equation 8) into the correlation function (Equation 1).

[0185] The unconfined compressive strength Qu can be expressed by the correlation function (Equation 9), which is the product of the water-to-powder ratio P and the reading S on the displacement scale. Qu = (3.94 × P + 1.49) × S (Equation 9)

[0186] Equation 9 shows the relationship between the reading S of the displacement scale, obtained by correcting the strength coefficient K by the water-to-powder ratio P, and the uniaxial compressive strength Qu.

[0187] To measure the uniaxial compressive strength Qu using this equation 9, the procedure is the same as in the first embodiment, except that the powder-to-water ratio P of the backfill grout 2 is obtained and input. That is, when the first flat section 171 is penetrated, the input value SN1 is determined from the reading S1, and when the second flat section 181 is penetrated, the input value SN2 is determined from the reading S2, and the measurement is performed by substituting the input value SN1 or SN2 into equation 3 to calculate the uniaxial compressive strength Qu.

[0188] Equation 9 shows the relationship between the input value SN, which is determined based on the reading S, the input value PN, which is determined based on the powder-to-water ratio P of the cement slurry, and the uniaxial compressive strength Qu.

[0189] By preparing Equation 9 in advance, the uniaxial compressive strength Qu of cement slurries with different powder-to-water ratios P ​​can be easily calculated and measured by measuring the reading S of the displacement scale of the cement slurry.

[0190] According to this embodiment, by determining a predetermined correlation function based on the relationship between the input reading, the input powder-water ratio, and the unconfined compressive strength, the unconfined compressive strength Qu can be easily and accurately measured for backfill injection material 2, which is a cement slurry with various powder-water ratios P.

[0191] [Eighth Embodiment] An eighth embodiment of the present invention will be described with reference to Figure 17, etc. Note that the same parts as in the first to seventh embodiments will be omitted from the explanation, and the following will mainly describe the parts that differ.

[0192] The eighth embodiment is a modified version of the seventh embodiment in which the correlation function (Equation 8) between the powder water ratio P and the strength coefficient K is shifted to the safer side.

[0193] The correlation function shown in Figure 17 is set by lowering the intercept of K = 3.94P + 1.49 so as to encompass all the plotted values.

[0194] In this case, the correlation function between the powder-to-water ratio P and the intensity coefficient K is expressed by the following equation. K=3.94×P+1.37 (Equation 10)

[0195] Therefore, similar to the seventh embodiment, the uniaxial compressive strength Qu can be expressed by the correlation function (Equation 11), which is the product of the water-to-powder ratio P and the reading S of the displacement scale. Qu = (3.94 × P + 1.37) × S (Equation 11)

[0196] By preparing Equation 11 in advance, the uniaxial compressive strength Qu of cement slurries with different powder-to-water ratios P ​​can be easily and safely calculated and measured by measuring the reading S of the displacement scale of the cement slurry.

[0197] [Ninth Embodiment] A ninth embodiment of the present invention will be described with reference to Figures 18 and 19, among other things. Note that the same parts as in the first to eighth embodiments will be omitted from the explanation, and the following will mainly describe the parts that differ.

[0198] The ninth embodiment differs from the first embodiment in that the first pressing portion 17 and the second pressing portion 18 of the penetration resistance indicator device 1 are detachable. Specifically, the second pressing portion 18, which has a second flat portion 181, has a connecting portion provided on the side opposite to the side that is positioned on the surface 21 of the backfill injection material 2, and the connecting portion is formed so that the first pressing portion 17, which has a first flat portion 171, can be connected to it.

[0199] Figure 18 shows the second pressing section of the penetration resistance indicator, with Figure 18(A) being a top view, Figure 18(B) a front view, and Figure 18(C) a bottom view. Figure 19 shows the penetration resistance indicator with the second planar section arranged, with Figure 19(A) a front view and Figure 19(B) a bottom view.

[0200] As shown in Figure 18, the second pressing portion 18 has a fitting recess 182 on its upper surface, which is the surface opposite to the second flat portion 181 that is positioned on the surface of the specimen of the backfill injection material. The fitting recess 182 is formed on a stepped portion 183 that is formed upward on the upper surface 180, and is formed so that the bottom surface of the first pressing portion 17 fits into it and becomes detachable.

[0201] As shown in Figure 19, the second pressing portion 18 can be attached to the rod 12 via the first pressing portion 17 by fitting the fitting recess 182 of the second pressing portion 18 into the bottom surface of the first pressing portion 17, which is fixed to the rod 12, and locking it in place. The fitting recess 182 corresponds to a connecting portion that is connected to the first planar portion of the present invention. To remove it, the locking between the fitting recess 182 of the second pressing portion 18 and the first pressing portion 17 is released and it is removed.

[0202] Furthermore, the hole (not shown) formed in the abutment flange 111 is opened to the extent that it can accommodate the stepped portion 183, and the penetration resistance indicator device 1 is configured such that when the rod 12 is fully immersed in the casing 11 against the biasing force of the elastic body 13, the indicator needle 15 points to the maximum scale of 40 mm on the movement scale 16.

[0203] If the fitting recess 182 is fitted and attached to the first flat portion 171 of the first pressing portion 17, the larger area of ​​the second flat portion 181 can be pressed evenly into the cement slurry. Furthermore, due to the fitting, when the entire penetration resistance indicator device 1, including the second flat portion 181, is withdrawn after penetrating the specimen of backfill injection material, the second pressing portion 18 can be withdrawn together with the first pressing portion 17 without leaving it inside the specimen, enabling efficient measurement work.

[0204] According to the penetration resistance indicator device 1 of this embodiment, the first flat portion 171 is attached to the tip side of the rod 12, and the second pressing portion 18 having the second flat portion 181 has a connecting portion provided on the side opposite to the side that is placed on the surface of the backfill material 2. The connecting portion can be connected to the first pressing portion 17 having the first flat portion 171, so that the large area of ​​the second flat portion 181 can be pressed evenly against the backfill material 2. Furthermore, when the entire penetration resistance indicator device 1, including the second flat portion 181, is withdrawn after being penetrated into the backfill material 2, the second flat portion 181 can be withdrawn together with the first flat portion 171 without leaving it in the backfill material 2, enabling efficient measurement work.

[0205] [Other variations] The present invention is not limited to the embodiments described above. For example, the following are also included.

[0206] In the embodiment of the present application, it was applied to the backfill injection material used for shield construction, but it is not limited to this and may be used for the driving method. Further, it may be applied not only to the backfill injection material but also to various other filling materials such as cement slurry. In the case of various other filling materials, if it is possible to level the surface after placement and confirm the strength at which the compaction machine can operate at an appropriate timing, labor saving in construction and early restoration of the embankment are possible.

[0207] In the embodiment of the present application, the configuration is such that the second flat portion is connected to the first flat portion attached to the rod member, but it may not be connected. It may simply be that the second flat portion is arranged on the surface of the cement slurry, the first flat portion is arranged on its upper surface, and the penetration resistance indicating device is penetrated and used. In this case, although it is necessary to separately recover the second flat portion remaining in the cement slurry, since it is not necessary to form a connecting portion in the second pressing portion, the cost can be reduced.

[0208] In the embodiment of the present application, the configuration is such that the second flat portion is connected to the first flat portion attached to the rod member and the second flat portion is used, but it is not limited to this. The first flat portion and the second flat portion may be configured to be detachable from the rod member, and the first flat portion and the second flat portion may be configured to be replaced and used.

[0209] It may also be used as an example by combining each technical matter in the embodiment including the modification and applying it to other embodiments.

Description of Reference Numerals

[0210] 1 Penetration resistance indicating device 11 Casing 111 Contact flange 12 Rod member 13 Elastic body 14 Opening 15 Indicator needle 16 Movement scale 17 First pressing portion 171 First flat portion 18 Second pressing portion 180 Upper surface 181 2nd plane part 182 Fitting recess 183 Multilayered section 2. Backfill injection material 20 Specimen 21 Surface

Claims

1. A penetration resistance indicator that shows the magnitude of resistance when penetrating into cement slurry, Casing and, A rod member provided to be retractable into the casing, An elastic body provided in the casing that biases the rod so that it protrudes from the casing, An indicator needle is provided on the rod and faces the opening of the casing, and moves in the direction of the rod's extension and retraction. A scale is provided facing the opening of the casing, and the amount of movement indicated by the indicator needle shows the amount by which the rod moves in the retraction direction against the biasing force of the elastic body, The first flat portion is located at the tip of the rod and is positioned on the surface of the cement slurry, The rod member comprises a second flat portion located at the tip end and positioned on the surface of the cement slurry, having a larger area than the first flat portion, A penetration resistance indicator device in which the first or second planar portion, which is located at the tip of the rod and positioned on the surface of the cement slurry, is pressed by the cement slurry, and the value of the movement scale pointed to by the indicator needle, which has moved due to the force received from the surface of the cement slurry, is read as the reading.

2. The first flat portion is attached to the tip side of the rod, The pressing portion having the second planar portion has a connecting portion provided on the side opposite to the side that is placed on the surface of the cement slurry, The penetration resistance indicator device according to claim 1, characterized in that the connecting portion is connectable to a pressing portion having the first planar portion.

3. The penetration resistance indicator according to claim 1, characterized in that the area of ​​the second planar portion is less than or equal to the area of ​​the first planar portion multiplied by the ratio of the weighing capacity of the movement amount scale to the scale division of the movement amount scale.

4. A method for measuring uniaxial compressive strength of a cement slurry, which measures the uniaxial compressive strength of a cement slurry from a predetermined correlation function based on the reading of a penetration resistance indicator device that shows the magnitude of resistance when penetrated into the cement slurry, The aforementioned penetration resistance indicator, Casing and, A rod member provided to be retractable into the casing, An elastic body provided in the casing that biases the rod so that it protrudes from the casing, An indicator needle is provided on the rod and faces the opening of the casing, and moves in the direction of the rod's extension and retraction. A scale is provided facing the opening of the casing, and the amount of movement indicated by the indicator needle shows the amount by which the rod moves in the retraction direction against the biasing force of the elastic body, The first flat portion is located at the tip of the rod and is positioned on the surface of the cement slurry, The rod member comprises a second flat portion located at the tip end and positioned on the surface of the cement slurry, having a larger area than the first flat portion, When the first or second planar portion is placed on the surface of the cement slurry and the penetration resistance indicator is driven into it, the tip of the rod and the first or second planar portion placed on the surface of the cement slurry are pressed against the cement slurry, and the value of the movement scale pointed to by the indicator needle, which has moved due to the force received from the surface of the cement slurry, is read as the magnitude of the resistance when the device is driven into the cement slurry. The predetermined correlation function shows the relationship between the input value determined based on the reading and the uniaxial compressive strength, The second planar portion is positioned on the tip side of the rod and on the surface of the cement slurry, and is driven in. Until the indicator needle points to the amount indicated on the displacement scale, the value indicated on the displacement scale by the indicator needle is taken as the reading, and the reading is multiplied by the ratio of the area of ​​the first planar portion to the area of ​​the second planar portion and input as the input value to the predetermined correlation function to measure the uniaxial compressive strength. A method for measuring uniaxial compressive strength, characterized in that the second planar portion is placed on the tip side of the rod and on the surface of the cement slurry and penetrated, and when the indicator needle points to a value greater than or equal to the amount of movement on the scale, the first planar portion is placed on the tip side of the rod and on the surface of the cement slurry, the first planar portion is pressed by the cement slurry, the value of the amount of movement scale pointed to by the indicator needle which has moved due to the force received from the surface of the cement slurry is taken as the reading, and the reading is input as the input value to the predetermined correlation function to measure the uniaxial compressive strength.

5. The predetermined correlation function is, The first flat portion is positioned on the tip side of the rod and on the surface of the cement slurry, and the reading obtained when the first flat portion is pressed against the cement slurry, and the uniaxial compressive strength of the cement slurry corresponding to the reading obtained, measured by a uniaxial compression testing machine, are used to determine the value. The method for measuring uniaxial compressive strength according to feature 4.

6. The predetermined correlation function is, This shows the relationship between the input value determined based on the aforementioned reading, the input value of the powder-to-water ratio determined based on the powder-to-water ratio of the cement slurry, and the uniaxial compressive strength. The second flat portion is positioned on the tip side of the rod and on the surface of the cement slurry, and is inserted. Until the indicator needle points to the measurement level on the displacement scale, the value on the displacement scale pointed to by the indicator needle is taken as the reading, and the value obtained by multiplying the reading by the ratio of the area of ​​the second flat portion to the second flat portion is taken as the input value, and the powder-to-water ratio of the cement slurry is input to the predetermined correlation function to measure the uniaxial compressive strength. The second flat portion is positioned on the tip side of the rod and on the surface of the cement slurry, and when the indicator needle moves to a position equal to or greater than the measurement amount on the displacement scale, the first flat portion is positioned on the tip side of the rod and on the surface of the cement slurry, and the first flat portion is pressed against the cement slurry. The value on the displacement scale pointed to by the indicator needle, which has moved due to the force received from the surface of the cement slurry, is taken as the reading, and the powder-to-water ratio of the cement slurry is input to the predetermined correlation function as the input value to measure the uniaxial compressive strength. The method for measuring uniaxial compressive strength according to claim 5, characterized in that

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