A device for measuring lateral friction and side wall soil pressure and a construction method thereof

Abstract

The present invention discloses a device for measuring side friction and side wall soil pressure and a construction method thereof, comprising: a box body, which is vertically arranged and has a groove on the outer side wall; a force transmission rod, which is hinged to the inner side wall of the groove; a tension pressure sensor, which includes two force-bearing ends arranged opposite to each other, which are respectively connected to the bottom surface of the force transmission rod and the inner bottom surface of the groove; a friction plate, which is located at the opening of the groove and connected to the free end of the force transmission rod, and the friction plate is perpendicular to the force transmission rod; two impermeable membranes, which cooperate with the friction plate to close the groove and form a sealed cavity; a pressure sensor, which is arranged on the outer side wall of the box body and the force-bearing end faces outward. By arranging the sensor inside the device, the present invention avoids the influence of the external harsh construction environment on the sensor, ensures the stability, accuracy and safety of the measuring device, can realize the real-time measurement of the side wall soil friction and side wall soil pressure, and calculates the friction coefficient of soil layers at different depths.

Description

Technical Field

[0001] The present invention relates to the field of building construction, and more specifically, to a device for measuring lateral friction and side wall earth pressure and a construction method thereof. Background Art

[0002] With the rapid development of large-span bridge construction, the construction of caisson foundations and pile foundations has also developed towards deeper construction areas, larger sizes, and more complex geological conditions. In order to ensure the quality of construction, higher requirements have been placed on parameter control during the construction process. Among them, the size of the side wall soil friction and end resistance are important control factors that determine whether the caisson can sink smoothly. During the sinking construction process, a soil pressure gauge is usually used to measure the side wall soil end surface pressure in real time. However, the measurement accuracy of this method is not high, and the soil pressure gauge is prone to damage during construction due to the lack of corresponding protective measures. At the same time, it is difficult to add additional measuring devices at the same position to obtain the side wall soil pressure value after the caisson is connected and sunk, and the full process control of the end surface pressure cannot be achieved. The side wall soil friction is usually determined by static load tests or self-balancing devices. There are technical problems such as complex test methods, large equipment volume, and inability to conveniently and accurately obtain the side friction of soil layers at different depths.

[0003] Therefore, there is an urgent need for a measuring device and method that can simultaneously measure the lateral friction and side wall soil pressure of the foundation structure in different soil layers at different depths, which can ensure measurement accuracy while being easy to operate and prevent damage to the measuring device caused by excessive pressure. Summary of the invention

[0004] The purpose of the present invention is to provide a device for measuring side friction and side wall soil pressure, which converts friction into the acting force between the force transmission rod and the tension pressure sensor through the linkage structure of the friction plate and the force transmission rod, and sets the sensor inside the device to avoid the influence of the external harsh construction environment on the sensor, thereby ensuring the stability, accuracy and safety of the measuring device. Another purpose of the present invention is to provide a construction method for the device for measuring side friction and side wall soil pressure, which can realize the real-time measurement of the side wall soil friction and side wall soil pressure during the construction of the foundation structure by flexibly installing it at different positions on the side wall of the foundation structure, and calculate the friction coefficient of soil layers at different depths.

[0005] In order to achieve these purposes and other advantages according to the present invention, a device for measuring side friction and side wall earth pressure is provided, comprising:

[0006] A box body is arranged vertically, and a groove is arranged on the outer side wall of the box body;

[0007] A force transmission rod is located inside the groove and is hinged to the inner side wall of the groove, and the force transmission rod rotates in the groove along the vertical direction;

[0008] A tension and pressure sensor, comprising two force-bearing ends arranged opposite to each other, which are respectively connected to the bottom surface of the force transmission rod and the inner bottom surface of the groove;

[0009] A friction plate, which is located at the opening of the groove and connected to the free end of the force transmission rod, the friction plate is perpendicular to the force transmission rod and has a height less than the height of the groove;

[0010] Two water-proof membranes are respectively arranged at the upper and lower ends of the friction plate, and the two water-proof membranes and the friction plate cooperate to close the groove and form a sealed cavity;

[0011] A pressure sensor is arranged on the outer side wall of the box body on the same side as the groove and located at the periphery of the sealed cavity, with the force-bearing end of the pressure sensor facing outwards;

[0012] The display device is electrically connected to the output end of the tension and pressure sensor and the output end of the pressure sensor through wires.

[0013] Preferably, in the side friction resistance and side wall earth pressure measuring device, when the friction plate is in a vertical state, the outer side wall of the friction plate and the force-bearing end of the pressure sensor and the outer side wall of the box connected to the pressure sensor are located in the same vertical plane.

[0014] Preferably, the side friction resistance and side wall earth pressure measuring device also includes a pad, which is arranged between the friction plate and the force transmission rod and fixed to the free end of the force transmission rod, the pad is parallel to the friction plate and is connected to the inner wall of the friction plate through a tooth groove structure, and one end of any water-impermeable membrane close to the friction plate is fixed between the friction plate and the pad through the tooth groove structure.

[0015] Preferably, the side friction resistance and side wall earth pressure measuring device also includes two protective plates, which are respectively located directly above and directly below the friction plate and correspond one-to-one to the two impermeable membranes. Any protective plate is fixed to the side wall of the box body by bolts, and there is a gap between the protective plate and the friction plate. One end of any impermeable membrane close to the protective plate is fixed between the corresponding protective plate and the box body.

[0016] Preferably, in the device for measuring the side friction resistance and side wall earth pressure, the waterproof membrane is a folded waterproof membrane, and during the process of the friction plate moving in the vertical direction, the vertical stress of the waterproof membrane on the friction plate is 0.

[0017] Preferably, in the device for measuring the side friction and side wall earth pressure, the groove is filled with a protective liquid, the volume of which is equal to the sealing volume of the sealing cavity.

[0018] Preferably, the side friction and side wall earth pressure measuring device further comprises a wiring protection tube, which is arranged on the outside of the box body, and the wire is connected to the display device through the wiring protection tube after passing through the box body.

[0019] The present invention also provides a construction method of a device for measuring side friction resistance and side wall earth pressure, comprising:

[0020] Step 1: Assemble the side friction resistance and side wall earth pressure measuring device as required. In the initial state, the force transmission rod is set horizontally and the pad is set vertically. After the assembly is completed, read the output value of the tension pressure sensor at this time, which is recorded as the initial pressure N0;

[0021] Step 2: Weld the side friction resistance and side wall earth pressure measuring device to the side wall of the foundation structure so that the outer side wall of the side friction resistance and side wall earth pressure measuring device and the outer side wall of the foundation structure are located on the same vertical plane;

[0022] Step 3: The foundation structure is constructed, and relative displacement occurs between the foundation structure and the external soil. At this time, the friction plate is subjected to continuous vertical friction, which drives the force transmission rod to rotate along the force direction and acts on the tension and pressure sensor. The output value of the tension and pressure sensor at this time is read and recorded as the real-time pressure N1.

[0023] Step 4: Set the distance from the connection point between the dowel rod and the tension and pressure sensor to the hinge point between the dowel rod and the groove as L1, the total length of the dowel rod as L0, and the surface area of ​​the contact surface between the friction plate and the external soil as A. The lateral friction resistance of the friction plate can be obtained by calculation:

[0024] Step 5: Read the output value of the pressure sensor during the foundation construction, recorded as F t , the friction coefficient between the foundation structure and the soil layer where the side friction resistance and side wall earth pressure measuring device is located can be obtained by calculation:

[0025] The present invention has at least the following beneficial effects:

[0026] 1. The present invention integrates the functions of measuring the side wall friction resistance and the side wall earth pressure when the caisson foundation and the pile foundation are sunk into the same measuring device, and there is no need to install different measuring devices respectively. The measuring device is small in size and easy and quick to install. It is suitable for foundation structure construction under various environments, and is conducive to measuring and controlling the side friction resistance and the side wall earth pressure at the same time, thereby ensuring the construction quality of the foundation structure, accelerating the construction progress and reducing the construction cost.

[0027] 2. The tension and pressure sensor is set in a closed cavity inside the measuring device and protected by a sealed box on the outside and a protective liquid inside. On the one hand, it will not be physically damaged by external impact. On the other hand, the sensor components with high environmental requirements are immersed in the protective liquid, which effectively prevents the electronic components from rusting and failing, resulting in inaccurate measurement results. The measurement precision and accuracy are high.

[0028] 3. Through the coordinated connection between the waterproof membrane and the protective plate, friction plate and metal pad, the force of the friction plate can be effectively transmitted to the force-transmitting steel rod, while ensuring the closure of the inner cavity of the box. At the same time, the waterproof membrane is a flexible structure, and the protective liquid in the inner cavity of the box is filled on the inner wall of the waterproof membrane, which can prevent external soil particles from embedding into the opening of the friction plate during the sinking process, thereby improving the stability of the device during the construction process and further improving the measurement accuracy.

[0029] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a schematic diagram of the front elevation structure of a device for measuring side friction and side wall earth pressure according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0032] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0033] like Figure 1 As shown, the present invention provides a device for measuring lateral friction and side wall earth pressure, comprising:

[0034] A box body 1 is arranged vertically, and a groove is provided on the outer side wall of the box body 1;

[0035] A force transmission rod 2, which is located inside the groove and hinged to the inner side wall of the groove, and the force transmission rod 2 rotates in the groove along the vertical direction;

[0036] A tension and pressure sensor 8, comprising two force-bearing ends arranged opposite to each other, which are respectively connected to the bottom surface of the force transmission rod 2 and the inner bottom surface of the groove;

[0037] A friction plate 7, which is located at the opening of the groove and connected to the free end of the force transmission rod 2, wherein the friction plate 7 is perpendicular to the force transmission rod 2 and has a height less than that of the groove;

[0038] Two water-impermeable membranes 4 are respectively arranged at the upper and lower ends of the friction plate 7, and the two water-impermeable membranes 4 and the friction plate 7 cooperate to close the groove and form a sealed cavity;

[0039] A pressure sensor 9 is arranged on the outer side wall of the box body 1 on the same side as the groove and located at the periphery of the sealed cavity, with the force-bearing end of the pressure sensor 9 facing outwards;

[0040] The display device is electrically connected to the output end of the tension and pressure sensor 8 and the output end of the pressure sensor 9 through the wires 10 respectively.

[0041] In the above technical scheme, the box body 1 is a closed structure surrounded by metal plates. The opening on the side wall of the box body 1 is provided with an inward groove. The inner wall of the groove is also welded by metal plates. The inner wall of the groove includes an inner top surface, an inner bottom surface and an inner side wall. A hinge joint 3 is provided in the middle of the inner side wall of the groove. The force transmission rod 2 is hinged to the inner side wall of the groove through the hinge joint 3. The tension and pressure sensor 8 is an S-type force sensor. The top and bottom surfaces of the tension and pressure sensor 8 are respectively provided with two force-bearing ends. The tension and pressure sensor 8 is located directly below the middle of the force transmission rod 2. The two force-bearing ends are respectively fixedly connected to the bottom surface of the force transmission rod and the inner bottom surface of the groove. The friction plate 7 is arranged at the opening of the groove. The outer wall surface of the friction plate is in direct contact with the soil outside the side friction resistance and side wall soil pressure measuring device. When the measuring device and the external soil are relatively displaced, the friction force along the moving direction received by the friction plate is the friction resistance between the measuring device and the external soil. The impermeable membrane 4 is made of high polymer materials such as rubber and is a flexible impermeable structure, which is used to close the gap between the friction plate 7 and the groove, so that the friction plate can move freely within the gap between the friction plate and the groove, and at the same time, the inner cavity of the groove is closed to prevent external soil, water or other impurities from entering the groove and affecting the normal operation of the tension and pressure sensors, force transmission rods and other devices. The pressure sensor 9 is located below the groove, and the force-bearing end of the pressure sensor 9 is set to face the external soil, and is used to measure the soil pressure received in the horizontal direction.

[0042] When the friction plate 7 is subjected to an upward friction force from the outside, it is affected by the hinge joint 3, and the friction plate 7 drives the force transmission rod 2 to rotate upward in the counterclockwise direction. At this time, the top force-bearing end of the tension and pressure sensor 8 is subjected to a tensile force from the force transmission rod 2, and the bottom force-bearing end is subjected to a tensile force from the bottom surface of the groove. The combined force of these two tensile forces is the upward friction resistance of the friction plate; when the friction plate 7 is subjected to a downward friction force from the outside, it is affected by the hinge joint 3, and the friction plate 7 drives the force transmission rod 2 to rotate downward in the clockwise direction. At this time, the bottom force-bearing end of the tension and pressure sensor 8 is subjected to a pressure from the bottom surface of the groove, and the top force-bearing end is subjected to a pressure from the force transmission rod 2. The combined force of these two pressures is the downward friction resistance of the friction plate. According to the real-time side wall friction resistance and side wall soil pressure measured by the tension and pressure sensor 8 and the pressure sensor 9, respectively, the dynamic friction coefficient is calculated according to the formula: Where f is the side wall soil friction resistance, N is the end face normal pressure (i.e. side wall soil pressure), and the friction coefficient of the soil layer where the measuring device is located can be obtained by conversion.

[0043] The present invention integrates the functions of measuring friction resistance and normal pressure into the same device. Since the direct measuring equipment (friction plate and pressure sensor) are arranged adjacently and the overall volume of the measuring device is small, relative to the foundation structure (caisson foundation, pile foundation), it can be considered that the tension and pressure sensors and the pressure sensors respectively measure the force data of the same point, thereby calculating the real-time friction coefficient between the measuring device and the soil layer and displaying it on the external display device. According to the position of the measuring device on the foundation structure and the depth of the soil layer entered during the construction process, the soil layer distribution of the construction environment and the friction coefficient of different soil layers can also be obtained, so that the construction personnel can adjust the construction parameters in time to ensure the stability and safety of the foundation structure construction. At the same time, the side wall friction resistance that is difficult to measure is converted into the force of the force transmission rod and the groove inside the device on the tension and pressure sensor, and a closed space is formed inside the groove, avoiding the influence of the construction environment and external displacement on the sensor measurement stability and accuracy during the foundation structure construction process, improving the measurement accuracy, effectively preventing the sensor from being damaged, and ensuring that the measuring device can smoothly sink with the foundation structure and perform measurement. In addition, the side friction resistance and side wall earth pressure measuring device has a simple structure and is easy to install, and can be quickly disassembled and assembled on the foundation structure. On the basis of ensuring stable measurement, it effectively controls construction costs and improves construction efficiency.

[0044] In another technical solution, in the device for measuring the side friction resistance and side wall soil pressure, when the friction plate 7 is in a vertical state, the outer side wall of the friction plate 7 and the force-bearing end of the pressure sensor 9 and the outer side wall of the box body 1 connected to the pressure sensor 9 are located in the same vertical plane. Specifically, in the initial position, the friction plate 7, the pressure sensor 9 and the outer side wall of the box body 1 form a continuous vertical plane. When the foundation structure is constructed, the box body 1 is embedded in the side wall of the foundation structure, and the outermost structures of the measuring device (the outer side wall of the box body, the friction plate, and the pressure sensor 9) are all located in the same plane as the outer side wall of the foundation structure. Therefore, when relative displacement occurs between the foundation structure and the external soil, the measuring device is connected to the foundation structure as a whole, and no additional force is generated on the external soil, which affects the construction of the foundation structure. Since the gap between the friction plate and the groove is set small and the length of the force transmission rod is relatively long, the rotation of the force transmission rod and the friction plate relative to the hinge joint can be approximately regarded as linear movement. Therefore, when the initial state of the friction plate is vertical, in the subsequent construction state, the friction plate always moves upward or downward in the vertical direction. The friction plate is always affected by the complete side wall soil friction resistance, driving the force transmission rod to move up and down, and transmitting the side wall soil friction resistance to the tension and pressure sensor, so that the value measured by the tension and pressure sensor is more accurate, reducing the influence of movement during construction on the measurement accuracy, and further reducing the measurement error.

[0045] In another technical solution, the side friction resistance and side wall earth pressure measuring device further includes a pad 5, which is arranged between the friction plate 7 and the force transmission rod 2 and fixed to the free end of the force transmission rod 2. The pad 5 is parallel to the friction plate 7 and is connected with the inner side wall of the friction plate 7 through a tooth groove structure. One end of any water-impermeable membrane 4 close to the friction plate 7 is fixed between the friction plate 7 and the pad 5 through the tooth groove structure. The pad 5 is a metal plate, which is arranged between the friction plate 7 and the force transmission rod 2. The force transmission rod 2 and the pad 5 are both made of metal materials with good durability and high rigidity, so that the force transmission rod 2 and the pad 5 can be better welded together, thereby improving the stability of the transmission structure. By means of the pad 5 which is arranged perpendicularly to the force transmission rod, the effective area of ​​the connection between the friction plate 7 and the transmission structure (the force transmission rod and the pad) is increased, and a tooth groove structure is provided on the side adjacent to the pad and the friction plate. The tooth groove structure can be designed to be serrated, U-shaped or threaded. The friction plate is connected with the corresponding tooth groove structure so that the friction plate can be stably engaged with the pad, further improving the stability of the transmission structure and preventing the connection between the friction plate and the pad from loosening or detaching when the friction resistance encountered by the friction plate is large, thereby preventing the measuring device from being unable to work normally.

[0046] In another technical solution, the side friction resistance and side wall earth pressure measuring device further includes two protective plates 6, which are respectively located directly above and directly below the friction plate 7 and correspond to the two impermeable membranes 4 one by one, and any protective plate 6 is fixed to the side wall of the box body 1 by bolts 12, and there is a gap 14 between the protective plate 6 and the friction plate 7, and one end of any impermeable membrane 4 close to the protective plate 6 is fixed between the corresponding protective plate 6 and the box body 1. Among them, the protective plate 6 above the friction plate 7 is installed on the side wall of the box body 1 in an inverted L shape, the horizontal part of the protective plate 6 is connected to the top surface of the box body 1, and the vertical part of the protective plate 6 is connected to the outer side wall of the box body 1, and the vertical part extends downward along the outer side wall of the box body 1 and covers the upper opening of the groove; the protective plate 6 below the friction plate is close to the outer side wall of the box body 1, one end of the protective plate 6 is connected to the top of the pressure sensor 9 below the groove, and the other end extends upward along the outer side wall of the box body and covers the lower opening of the groove. When the friction plate 7 is in the initial state, the friction plate 7 is arranged vertically, and the two protective plates 6, the friction plate 7 and the force-bearing ends of the pressure sensor 9 are located in the same vertical plane. The protective plate 6 is used to protect the outer wall of the box body that is in direct contact with the external soil, and prevent the external environment from directly causing damage to the box body; at the same time, the protective plate 6 can cover a part of the corresponding impermeable membrane, reduce the surface area of ​​the impermeable membrane that is in direct contact with the soil, and prevent impurities in the external soil from scratching or destroying the sealing of the impermeable membrane. In addition, one end of the impermeable membrane 4 is arranged between the protective plate 6 and the outer wall of the box body 1, and the other end is fixed between the friction plate 7 and the pad 5 through a tooth groove structure, so that the connection between the two ends of the impermeable membrane and the measuring device is stable and reliable, not easy to loosen, ensuring the sealing performance inside the groove, and improving the stability of the overall measuring device.

[0047] In another technical solution, in the device for measuring the side friction and side wall earth pressure, the impermeable membrane 4 is a folded impermeable membrane, and in the process of the friction plate 7 moving in the vertical direction, the vertical stress of the impermeable membrane 4 on the friction plate 7 is 0. Specifically, the height of the gap 14 between the friction plate and the corresponding protective plate needs to be set according to the maximum friction value and the corresponding friction coefficient set in actual construction, so as to allow the friction plate to move within the set range and transmit the side friction. The two ends of the watertight membrane 4 are respectively fixed on the box body and the friction plate. The middle part of the watertight membrane is in a folded state in the initial state. The folded length (i.e., the length increased in the vertical direction when the watertight membrane is opened) needs to be greater than the set unidirectional maximum displacement of the friction plate. Therefore, when the force transmission rod and the friction plate move, the watertight membrane is always in a state without tension. Correspondingly, due to the absence of elastic deformation, there is no vertical stress on the friction plate by the watertight membrane, so that the friction plate will not be subjected to vertical forces other than the lateral friction resistance of the external soil and gravity during the movement. In this way, the force transmitted to the tension and pressure sensor can be equivalent to the lateral friction resistance, and will not be interfered by the watertight membrane to cause inaccurate measurement values, thereby ensuring measurement accuracy.

[0048] In another technical solution, the side friction and side wall earth pressure measuring device is filled with a protective liquid 11 in the groove, and its volume is equal to the sealed volume of the sealed cavity. The protective liquid is preferably hydraulic oil, which completely fills the sealed cavity in the groove and has an anti-corrosion effect, which can effectively prevent the tension and pressure sensors and other metal structures inside the groove from rusting, and at the same time play a lubricating role on the transmission structure, reducing the influence of the friction force generated by the assembly connection between the force transmission rod 2 and the hinged head 3 on the rotation of the force transmission rod, so that the degree of the measured tension and pressure sensor is equal to the actual side friction resistance of the friction plate, thereby ensuring the accuracy of the measurement.

[0049] In another technical solution, the side friction and side wall earth pressure measuring device further includes a wiring protection tube 13, which is arranged on the outside of the box body 1. After the wire 10 passes through the box body 1, it is connected to the display device through the wiring protection tube 13. In the above technical solution, the wiring protection tube 13 is made of building pipes such as metal pipes and PVC pipes. The wiring protection tube is fixed to the bottom of the box body 1. The connection between the two is sealed to prevent water vapor or impurities from entering. Two bundles of wires 10 are respectively connected to the output ends of the tension and pressure sensors and the pressure sensors, and pass through the wiring protection tube to be connected to the input end of the display device, thereby preventing the output signal of the sensor from being interfered by the external environment during the construction of the infrastructure and ensuring the stability of signal transmission.

[0050] The present invention also provides a construction method of a device for measuring side friction resistance and side wall earth pressure, comprising:

[0051] Step 1: Assemble the side friction resistance and side wall earth pressure measuring device as required. In the initial state, the force transmission rod 2 is set horizontally and the pad 5 is set vertically. After the assembly is completed, read the output value of the tension pressure sensor 8 at this time, which is recorded as the initial pressure N0;

[0052] Step 2: Weld the side friction resistance and side wall earth pressure measuring device to the side wall of the foundation structure so that the outer side wall of the side friction resistance and side wall earth pressure measuring device and the outer side wall of the foundation structure are located on the same vertical plane;

[0053] Step 3: The foundation structure is constructed, and relative displacement occurs between the foundation structure and the external soil. At this time, the friction plate 7 is subjected to continuous vertical friction force, which drives the force transmission rod 2 to rotate along the force direction and acts on the tension and pressure sensor 8. The output value of the tension and pressure sensor 8 at this time is read and recorded as the real-time pressure N1;

[0054] Step 4: Set the distance from the connection point between the dowel rod 2 and the tension and pressure sensor 8 to the hinge point between the dowel rod 2 and the groove as L1, the total length of the dowel rod 2 as L0, and the surface area of ​​the contact surface between the friction plate 7 and the external soil as A. The lateral friction resistance of the friction plate 7 can be obtained by calculation:

[0055] Step 5: Read the output value of the pressure sensor 9 during the construction of the foundation structure, recorded as F t , the friction coefficient between the foundation structure and the soil layer where the side friction resistance and side wall earth pressure measuring device is located can be obtained by calculation:

[0056] Through the above construction method, the side friction resistance and end pressure of the foundation structure during the construction of the foundation structure can be measured and monitored in real time, and the construction parameters can be adjusted in time according to the displayed data to ensure the smooth progress of the foundation construction and improve the construction stability, safety and quality. At the same time, the friction coefficient distribution of the soil layer in the construction area can be calculated based on the pressure data obtained from a single construction, which has a high guiding significance for subsequent construction.

[0057] In this embodiment, the method of assembling the side friction resistance and side wall earth pressure measuring device in step 1 is as follows:

[0058] S1, using metal plates to weld the box body 1 and the grooves on its side walls to form an internally closed whole;

[0059] S2, install the hinge joint 3 and the force transmission rod 2 in the groove, and install the tension and pressure sensor 8 under the force transmission rod, so that the two force-bearing ends of the tension and pressure sensor are respectively connected and fixed to the bottom surface of the force transmission rod and the inner bottom surface of the groove, and the force transmission rod 2 is set horizontally after installation;

[0060] S3. A pad 5 perpendicular to the force transmission rod 2 is installed at the free end thereof, and a friction plate 7 is arranged on the outer side of the pad 5, and the friction plate 7 is parallel to the pad 5. Here, when the foundation structure is a concrete structure, the friction plate 7 adopts a cast-in-place concrete plate, and a continuous tooth groove structure is arranged on the outer side wall of the pad 5, and the friction plate 7 is clamped with the pad 5 through the tooth groove structure; when the outer wall of the foundation structure is steel, the friction plate 7 adopts a metal plate, and the friction plate is fixed to the outer side of the pad by tightening the rivets between the friction plate 7 and the pad 5;

[0061] S4. Two protective plates 6 are respectively arranged above and below the friction plate 7. The protective plates 6 are closely connected to the outer wall of the box body 1 and cover a part of the opening of the groove. The box body is placed on its side with the opening of the groove facing upward, and hydraulic oil is injected into the groove as a protective liquid until the hydraulic oil completely fills the groove.

[0062] S5. Install the waterproof membrane. One end of the waterproof membrane 4 is first inserted into the part where the protective plate and the box body are fitted. A rubber band is used to preliminarily fix one end of the waterproof membrane 4 to the part where the protective plate extends out of the groove opening. The other end is inserted into the connection structure between the friction plate and the pad. A rubber band is used to preliminarily fix the other end of the waterproof membrane between the friction plate and the pad. Then, respectively tighten the bolts between the protective plate 6 and the box body 1, and re-fix the connection structure between the friction plate and the pad, so that the two ends of the waterproof membrane are respectively fixed between the protective plate and the box body, and between the friction plate and the pad. At this time, a closed space (sealed cavity) is formed inside the groove.

[0063] S5. Install a pressure sensor 9 on the periphery of the groove and fix it on the outer wall of the box 1 on the same side as the groove. Connect wires 10 from the output ends of the pressure sensor 9 and the tension pressure sensor 8 respectively. Install a wiring protection tube 13 at the bottom of the box. Pass the wires 10 through the wiring protection tube and connect them to an external display device.

[0064] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A device for measuring lateral friction and side wall earth pressure, characterized in that: include: A box body is arranged vertically, and a groove is arranged on the outer side wall of the box body; A force transmission rod is located inside the groove and is hinged to the inner side wall of the groove, and the force transmission rod rotates in the groove along the vertical direction; A tension and pressure sensor, comprising two force-bearing ends arranged opposite to each other, which are respectively connected to the bottom surface of the force-transmitting rod and the inner bottom surface of the groove; A friction plate, which is located at the opening of the groove and connected to the free end of the force transmission rod, the friction plate is perpendicular to the force transmission rod and has a height less than the height of the groove; Two water-proof membranes are respectively arranged at the upper and lower ends of the friction plate, and the two water-proof membranes cooperate with the friction plate to close the groove and form a sealed cavity; A pressure sensor is arranged on the outer side wall of the box body on the same side as the groove and located at the periphery of the sealed cavity, with the force-bearing end of the pressure sensor facing outwards; A display device, which is electrically connected to the output end of the tension and pressure sensor and the output end of the pressure sensor through wires; Wherein, when the friction plate is in a vertical state, the outer wall of the friction plate, the force-bearing end of the pressure sensor, and the outer wall of the box connected to the pressure sensor are located in the same vertical plane; the groove is filled with protective liquid, and its volume is equal to the sealing volume of the sealing cavity.

2. The device for measuring lateral friction and side wall earth pressure according to claim 1, characterized in that: It also includes a pad, which is arranged between the friction plate and the force transmission rod and fixed to the free end of the force transmission rod. The pad is parallel to the friction plate and is connected to the inner wall of the friction plate through a tooth groove structure. One end of any water-impermeable membrane close to the friction plate is fixed between the friction plate and the pad through the tooth groove structure.

3. The device for measuring lateral friction and side wall earth pressure according to claim 2, characterized in that: It also includes two protective plates, which are respectively located directly above and below the friction plate and correspond one-to-one to the two watertight membranes. Any protective plate is fixed to the side wall of the box body by bolts. There is a gap between the protective plate and the friction plate. One end of any watertight membrane close to the protective plate is fixed between the corresponding protective plate and the box body.

4. The device for measuring lateral friction and side wall earth pressure according to claim 3, characterized in that: The waterproof membrane is a folded waterproof membrane. When the friction plate moves in the vertical direction, the vertical stress of the waterproof membrane on the friction plate is 0.

5. The device for measuring lateral friction and side wall earth pressure according to claim 1, characterized in that: It also includes a wiring protection tube, which is arranged on the outside of the box body. After the wire passes through the box body, it is connected to the display device through the wiring protection tube.

6. A construction method of the device for measuring lateral friction and side wall earth pressure as claimed in claim 1, characterized in that: include: Step 1: Assemble the side friction resistance and side wall earth pressure measuring device as required. In the initial state, the force transmission rod is set horizontally and the pad is set vertically. After the assembly is completed, read the output value of the tension pressure sensor at this time, which is recorded as the initial pressure N0; Step 2: Weld the side friction resistance and side wall earth pressure measuring device to the side wall of the foundation structure so that the outer side wall of the side friction resistance and side wall earth pressure measuring device and the outer side wall of the foundation structure are located on the same vertical plane; Step 3: The foundation structure is constructed, and relative displacement occurs between the foundation structure and the external soil. At this time, the friction plate is subjected to continuous vertical friction, which drives the force transmission rod to rotate along the force direction and acts on the tension and pressure sensor. The output value of the tension and pressure sensor at this time is read and recorded as the real-time pressure N1. Step 4: Set the distance from the connection point between the dowel rod and the tension and pressure sensor to the hinge point between the dowel rod and the groove as L1, the total length of the dowel rod as L0, and the surface area of ​​the contact surface between the friction plate and the external soil as A. The lateral friction resistance of the friction plate can be obtained by calculation: ; Step 5: Read the output value of the pressure sensor during the foundation construction, recorded as F t , the friction coefficient between the foundation structure and the soil layer where the side friction resistance and side wall earth pressure measuring device is located can be obtained by calculation: .

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