CN206829205U - Measuring system for tensile force of prestressed steel strand anchor cable - Google Patents

Abstract

The utility model discloses a detection system for the tensile force of a prestressed steel strand anchor cable, which comprises a steel strand, a rock mass, a supporting plate, an anchor tool, and an anchor body. A drill hole is arranged on the rock mass, and a The anchor solidly connected with the rock mass; one end of the steel strand is anchored in the anchor at the bottom of the borehole through the drill hole, and the other end of the steel strand passes through the supporting plate and the anchorage; In the rock mass; the anchor is kept in contact with the supporting plate; the anchor is provided with an acceleration sensor and a vibrator, and the acceleration sensor is connected to a computer. The utility model has the advantages of simple structure, low detection cost and safe and reliable use. It can not only meet the requirements of large-area detection, but also can adapt to the effective tension of various fastening components composed of steel strands and supporting anchors for steel strands. Pull detection.

Description

Measuring system for tensile force of prestressed steel strand anchor cable

technical field

The utility model relates to an anchoring force detection device for anchoring a rock mass by supporting steel strands and anchorages, in particular to a detection system for the tensile force of prestressed steel strands and anchor cables.

Background technique

The prestressed steel strand anchor cable anchoring technology has been widely used for its remarkable technical and economic benefits. As early as 1980, the coal mine reinforcement project in North Wales first appeared to use steel bars to strengthen the rock formation. In 1934, the heightening project of the Sherfa Dam in Algeria was the first to use prestressed steel strand anchor cables. For the first time in 1964, prestressed steel strand anchor cables were used in the dam foundation reinforcement of Meishan Reservoir. The early prestressed steel strand anchor cables used steel wire ropes, and the supporting anchorages were poor in reliability, resulting in low anchorage efficiency. With the introduction of high-strength steel strands and supporting anchors into my country, my country's self-manufactured high-strength steel strands and supporting anchors with high anchorage efficiency are widely used in structures and bridges to apply prestress, forming corresponding high-strength steel strands and supporting anchors. According to national standards, the development of prestressed steel strand anchor cable anchoring engineering technology is particularly rapid, and it has almost touched the anchoring support of high slopes, dams, and deep foundation pits in civil buildings. In particular, the widespread phenomenon of high filling and deep excavation makes the anchoring technology of prestressed steel strand anchor cables particularly important. It is an active support method, and the active pressure provided to the rock mass (rock and soil mass) can effectively limit the The slope surface of the body is deformed and its stability is maintained, which greatly improves the stress conditions of the supporting structure, not only reduces the self-weight of the structure itself, saves engineering materials, but more importantly, in the area where the side limit is strictly limited, the supporting structure The use of prestressed steel strand anchor cables shows its unique advantages. For example, deep foundation pit pile anchor technology, slope frame prestressed steel strand anchor cable support structure, etc. are very successful applications. However, in the process of construction and use, prestressed steel strand anchor cables will inevitably experience a certain amount of prestress loss. The loss factors include anchorage system retraction, reinforcement relaxation, soil rheological compression, etc. How to make the prestressed steel strand The long-term stable prestress of strand anchor cables is a basic factor related to the success or failure of reinforcement projects. If the prestress is significantly smaller than the design value, the anchoring function will fail; if the prestress is significantly greater than the design value (overtension), the anchor may be damaged. Based on this, in order to ensure effective anchoring functions and prestressed steel strand anchor cables For the safety during use, it is necessary to evaluate the prestressing effectiveness of the prestressed steel strand anchor cable with the help of convenient and reliable detection means. At present, the detection method is to convert the prestress by obtaining the strain by installing sensors, attaching strain gauges, and sound wave distance measurement through rod drilling. The cost is too high and inconvenient for large projects, and it is only suitable for scientific research; there is also the oil meter control method. It is low (rough judgment on loss) and cannot monitor the prestress of prestressed steel strand anchor cables for a long time.

Utility model content

In order to solve the above technical problems, the utility model provides a simple structure, low detection cost, using safe and reliable prestressed steel strand anchor cable tension detection system, which can not only meet the requirements of large-area detection, but also can be adapted by Detection of the effective tensile force of various fastening components composed of steel strands and anchorages for steel strands.

The technical scheme adopted by the utility model is: a detection system for the tensile force of the prestressed steel strand anchor cable, including steel strand, rock mass, supporting plate, anchorage, and anchor body. The bottom of the hole is provided with an anchor solidly connected with the rock mass; one end of the steel strand is anchored in the anchor at the bottom of the drill hole through the drill hole, and the other end of the steel strand passes through the supporting plate and the anchorage; the supporting plate is set at the opening of the drilling hole anchored in the rock mass; the anchor is kept in contact with the supporting plate; the anchor is provided with an acceleration sensor and a vibrator, and the acceleration sensor is connected to the computer.

In the above-mentioned detection system for the tensile force of the prestressed steel strand anchor cable, the acceleration sensor is fixedly installed on the end surface of the anchorage device via a magnetic suction seat or rubber mud or gypsum mud.

In the above-mentioned detection system for the tensile force of the anchor cable of the prestressed steel strand, the vibration direction of the acceleration sensor is parallel to the axis of the anchored steel strand.

In the above-mentioned detection system for the tensile force of the anchor cable of the prestressed steel strand, the anchored steel strand is provided with or without an exposed section.

In the above-mentioned detection system for the tensile force of the prestressed steel strand anchor cable, the material used for the anchor body is a material that can consolidate the rock mass, the steel strand, and the anchor material.

Compared with the prior art, the beneficial effects of the utility model are:

(I) The detection system of the utility model has a simple structure, which can not only meet the requirements of large-area detection, but also realize effective tensioning of various fastening components composed of steel strands and anchorages matched with steel strands. Detection of tension; especially suitable for detection of tension of prestressed steel strand anchor cables for rock (soil) anchorage.

(II) The vibrator of this utility model can be applied to a system for testing vibration information of various types of steel strands and anchorages matched with steel strands; the acceleration sensor of this utility model is a magnetic suction seat or rubber mud Or if the gypsum mud is fixedly connected to the end face of the anchorage supporting the steel strand, it is very convenient to connect or separate from the end face of the anchorage supporting the steel strand, which improves the rapid monitoring ability of the testing system.

(Ⅲ) The utility model has the functions of fast, repeated installation and safe use.

(Ⅳ) The utility model completely solves the problem of failure caused by excessive prestress loss of rock (soil) anchorage, and is useful for preventing the failure of prestressed steel strand anchor cable reinforcement structure and improving the stability and reliability of reinforced slopes and foundation pits. Sex plays an important role, and the business prospects are very impressive.

Description of drawings

Fig. 1 is the front view of the utility model.

Fig. 2 is an enlarged view of A in Fig. 1 .

Fig. 3 is a structural diagram of the detection system when the anchor cable of the prestressed steel strand of the present invention does not have an exposed section.

detailed description

Below in conjunction with accompanying drawing, the utility model is described in further detail.

As shown in Figures 1-3, the detection system for the tensile force of the prestressed steel strand anchor cable of the present invention includes a steel strand 1, a rock mass 2, a borehole 3, a supporting plate 4, an anchor 5, and an anchor 11. The rock mass 2 is provided with a borehole 3 , and the bottom of the borehole 3 is provided with an anchoring body 11 fixedly connected with the rock mass 2 . One end of the steel strand 1 is anchored in the anchor body 11 at the bottom of the borehole 3 through the borehole 3 , and the other end of the steel strand 1 passes through the supporting plate 4 and the anchorage 5 . The supporting plate 4 is placed at the opening of the borehole 3 and anchored in the rock mass 2, and the anchorage 5 is kept in contact with the supporting plate 4. The anchor 5 is provided with an acceleration sensor 7 and a vibrator 8 , and the acceleration sensor 7 is connected to a computer 10 . The material used for the anchoring body 11 is a material that can make the rock mass 2, the steel strand 1, and the anchoring material 111 consolidated with each other.

The anchor 5 is provided with an acceleration sensor 7 and a vibrator 8; the acceleration sensor 7 is fixedly installed on the end face of the anchor through a magnetic suction seat 71, and can also be fixed on the end face of the anchor through rubber mud or gypsum mud. The vibration direction of the acceleration sensor 7 is parallel to the axis of the steel strand 1 after tension. The acceleration sensor 7 is connected to the computer 10 through the data collector 9 , and the data collector 9 is connected to the power supply 103 . The computer 10 is provided with a signal analysis device 101 and a natural frequency calculation module 102 for connecting the data collector 9 .

The detection method of the tensile force of the prestressed steel strand anchor cable of the present utility model comprises the following steps:

1) According to the design drawings of the retaining structure, carry out the construction setting out, determine the position of the drilling 3 of the supporting structure of the rock mass 2, and construct the drilling 3 in the rock mass 2; inject anchor material into the drilling 3 to make it At the bottom of the borehole 3, an anchoring body 11 is formed that is mutually affixed to the rock mass 2; one end of the steel strand 1 reaches the bottom of the borehole 3 through the borehole 3, and is anchored in the anchoring body 11 at the bottom of the borehole 3; The other end of the line 1 passes through the supporting plate 4 and the anchor 5, and the supporting plate 4 is placed at the opening of the borehole 3, and anchored in the rock mass 2, and the anchor 5 is kept in contact with the supporting plate 4.

2) After the anchoring body 11 reaches the anchoring strength, one end of the steel strand 1 passing through the anchor 5 is stretched, and the steel strand 1 becomes a prestressed steel strand anchor cable 1a after locking the anchor 5 .

3) Set the acceleration sensor 7 and the vibrator 8 on the end face of the anchorage 5, and connect the acceleration sensor 7 to the computer 10 through the data collector 9.

4) Operate the computer 10, and the computer 10 sends out a signal collection command to control the action of the vibrator 8 to make the anchorage 5 vibrate, and the vibration signal of the anchorage 5 is transmitted back to the computer 10 through the data collector 9.

5) Process the collected vibration signal of the anchorage 5 to obtain the first-order vibration frequency of the system composed of the prestressed steel strand anchor cable 1a and the anchorage 5 in the length direction of the prestressed steel strand anchor cable 1a. The first-order vibration frequency obtains the tension force of the prestressed steel strand anchor cable 1a.

6) The signal analysis device 101 processes the collected vibration signal of the anchorage 5 to obtain the first-order vibration of the system composed of the prestressed steel strand anchor cable 1a and the anchorage 5 vibrating in the length direction of the prestressed steel strand anchor cable 1a Frequency, the natural frequency calculation module 102 obtains the tension force of the prestressed steel strand anchor cable 1a according to the first-order vibration frequency.

The natural frequency calculation module 102 calculates the tensile force of the prestressed steel strand anchor cable 1a according to the following two calculation formulas;

In the formula: is the normal contact stiffness between the anchor 5 and the supporting plate 4, Be the first-order vibration frequency of the vibration system of the system consisting of prestressed steel strand anchor cable 1a and anchorage 5 in the lengthwise direction of prestressed steel strand anchor cable 1a, T the tensile force of prestressed steel strand anchor cable 1a, The length of the vertical prestressed tendon 1a of the steel strand, is the elastic modulus unit of steel strand 1, is the mass of 1 unit length of steel strand, It is the sum of the mass of the anchorage 5 and the mass of the exposed section 6.

Example A

① The construction unit carries out construction laying out according to the design drawings of the retaining structure, determines the position of the drill hole 3 of the retaining structure of the rock mass 2, and constructs the borehole 3 in the rock mass 2; injects anchoring material into the borehole 3, so that The bottom of the borehole 3 forms an anchor 11 that is mutually consolidated with the rock mass 2; one end of the steel strand 1 reaches the bottom of the borehole 3 through the borehole 3, and is anchored with the anchor 11 at the bottom of the borehole 3; The other end of the line 1 passes through the supporting plate 4 and the anchor 5, and the supporting plate 4 is placed at the opening of the borehole 3, and anchored in the rock mass 2, and the anchor 5 is kept in contact with the supporting plate 4.

After the anchoring body 11 reaches the anchoring strength, it is stretched through one end of the steel strand 1 of the anchorage 5, and the steel strand 1 becomes the prestressed steel strand anchor cable 1a after locking the anchorage 5; the prestressed steel strand anchor cable 1a The outer end is provided with an exposed section 6 as required. The length of the exposed section 6 must be reserved when the steel strand 1 is stretched. The length should ensure the reliability and safety of the tensioning process. After the tension of the exposed section 6 reaches the design requirements It can be cut, that is, to form a detection system without the exposed length 6 as shown in FIG. 3 .

② An acceleration sensor 7 and a vibrator 8 are arranged on the anchorage 5, the acceleration sensor 7 is electrically connected with the data collector 9, the computer 10 and the power supply 103, and the signal analysis device 101 for connecting the data collector 9 is installed and operated on the computer In 10, operate the computer 10, click the signal acquisition command in the interface of the signal analysis device 101, the vibrator 8 gets an instruction action, and the vibrator 8 makes the prestressed steel strand anchor cable 1a, the anchorage 5, and the exposed section 6 vibrate ( When the exposed section 6 is set), the vibration signal of the anchorage 5 is converted by the signal analysis device 101 into the natural frequency of the vibration of the prestressed steel strand anchor cable 1a, the anchorage 5, and the exposed section 6 (when the exposed section 6 is set) and is determined by the signal The analysis device 101 interface display, and the tension of the prestressed steel strand anchor cable 1a in the signal analysis device 101 is used to vibrate with the prestressed steel strand anchor cable 1a, the supporting anchorage 5 and the exposed section 6 of the steel strand 1 (set The natural frequency calculation module 102 of the exposed section 6) to obtain the tension force of the prestressed steel strand anchor cable 1a.

Example B

①The process of transforming steel strand 1 into prestressed steel strand anchor cable 1a is completed through construction operations. -5 model anchorage 5 is taken as an example, the diameter of its steel strand 1 is 15.2 mm, and the number of 1 steel strand is 5.

②Acceleration sensor 7 is fixedly installed on the end face of anchorage 5 through magnetic suction seat 71 (or rubber mud or gypsum mud). The vibration direction of acceleration sensor 7 should be parallel to the length direction of prestressed steel strand anchor cable 1a, as shown in Figure 1, As shown in 3, the acceleration sensor 7 is an optional YD-65 product with a charge sensitivity of 414.15, a frequency measurement range of 5 to 2000 Hz, and a matching magnetic suction seat 71.

③ Select DH-5922 data collector 9 for the acceleration sensor, and connect the acceleration sensor 7 with a shielded cable through the matching charge adapter H5857-1. The socket of the supporting charge adapter H5857-1 of the device 9 is connected.

④ The data collector 9 is connected with the computer 10 using a 1394 connection.

⑤Connect the data collector 9, use the signal analysis device 101 to install and run in the computer 10 and match the data collector 9, input the sensitivity coefficient of the acceleration sensor 7 according to the operation instructions of the signal analysis device 101 supporting the data collector 9, click the data The signal acquisition interface of the collector 9 starts signal acquisition, and the vibrator 8 is used. The vibrator 8 should be able to make the prestressed steel strand anchor cable 1a and the anchorage 5 vibrate, and can be used to test various vibration information detection In the system, the vibration button of the vibrator 8 is manually activated to vibrate the end face of the anchorage 5. The direction of the vibration should be parallel to the length direction of the prestressed steel strand anchor cable 1a. After 3 seconds, click the data collector 9 to form a complete set. The stop collection interface of the signal analysis device 101 operates the signal analysis device 101 according to the coefficient specification, and performs frequency analysis on the intercepted vibration signal to obtain the natural frequencies of the prestressed steel strand anchor cable 1a, the anchorage 5, and the exposed section 6.

⑥Calculation of tension force of prestressed steel strand anchor cable 1a.

1) Calculation principle of 1a tensile force of prestressed steel strand anchor cable:

Considering the prestressed steel strand anchor cable 1a, the anchorage 5, and the exposed section 6 are vibrating systems in the length direction of the prestressed steel strand anchor cable 1a, different tensile forces make the anchorage 5 and the supporting plate 3 have different normal directions contact stiffness k , the vibration system of the prestressed steel strand anchor cable 1a, the anchorage 5, and the exposed section 6 in the length direction of the prestressed steel strand anchor cable 1a have different natural vibration frequencies , using the natural frequency The relationship between the normal contact stiffness k of the anchorage 5 and the supporting plate 3, by testing the natural frequency , infer the normal contact stiffness k between the anchor 5 and the supporting plate 3, and obtain the tensile force from the change of the normal contact stiffness k between the anchor 5 and the supporting plate 3.

Calculate the tensile force according to the following two formulas:

(1)

In the formula: is the normal contact stiffness between the anchor 5 and the supporting plate 3, is the first-order vibration frequency of the vibration system of the prestressed steel strand anchor cable 1a, the anchorage 5, and the exposed section 6 in the length direction of the prestressed steel strand anchor cable 1a. in is the elastic modulus unit of steel strand 1, Prestressed steel strand anchor cable 1a length, is the cross-sectional area of steel strand 1 (when multiple steel strands 1 are the total cross-sectional area of multiple steel strands 1, this example includes five steel strands 1, is 5 times the cross-sectional area of the steel strand 1 with a diameter of 15.2 mm), is the mass of 1 unit length of the steel strand (the calculation method is the same as the cross-sectional area), is the sum of the mass of the anchorage 5 and the mass of the exposed section 6, and the mass of the exposed section 6 = , is the length of the exposed segment 6; when the exposed segment 6 is not set, the value of L1 is 0.

Calculated from formula (1) Substitute into the following formula:

(unit: kN) (2)

T is the tensile force of the prestressed steel strand anchor cable 1a.

In the above embodiment, When the exposed section is set: the prestressed steel strand anchor cable L=4m, the length of the exposed section 6 L1=0.8m, and the measured first-order vibration frequency is =845.5× , prestressed steel strand anchor cable 15.2mm, modulus of elasticity = 1.96×10 ⁹ MPa, mass M of JYM15.2-5 type anchorage = 3.32kg. Substituting the calculation parameters into the formula (1) to get =212058245N/m. Substituting into (2) the tension force T=255.7kN. When there is no exposed section: prestressed steel strand anchor cable L=4m, the measured first-order vibration frequency is =846.0× , prestressed steel strand anchor cable 15.2mm, modulus of elasticity = 1.96×10 ⁹ MPa, mass M of JYM15.2-5 type anchorage = 3.32kg. Substituting the calculation parameters into the formula (1) to get =187790613N/m. Substituting (2) into the tension force T = 212.0kN.

The above are only preferred embodiments of the present utility model, and those skilled in the art can also make various modifications and transformations to this according to the above-mentioned concept of the present utility model. For example, the prestressed steel strand anchor cable 1a is provided with or without the exposed section 6, and cement mortar is poured into the borehole, etc., and the anchor material is changed. The acceleration sensor 7 is installed, and the acceleration sensor 7 is installed at different positions on the end face of the anchorage 5, the signal analysis device 101 and the computer 10 are combined into one, and the principle relationship is solidified in the combined instrument, the signal The collector 9 and the computer 10 are connected to each other and the structure is modified and transformed, and the calculation relation is corrected without changing the principle. The vibration mode of the vibrator is changed, however, similar transformations and modifications all belong to the essence of the present utility model.

Claims (5)

1. A kind of 1. detecting system of prestress wire anchorage cable stretching power, it is characterised in that：Including steel strand wires（1）, rock mass（2）、 Supporting plate（4）, anchorage（5）And anchoring body（11）, rock mass（2）It is provided with drilling（3）, drilling（3）Bottom is provided with and rock mass（2）It is affixed Anchoring body（11）；Steel strand wires（1）One end passes through drilling（3）It is anchored at drilling（3）The anchoring body of bottom（11）It is interior, steel strand wires （1）The other end pass through supporting plate（4）And anchorage（5）；Supporting plate（4）It is arranged on drilling（3）Aperture at, be anchored in rock mass（2）In； Anchorage（5）With supporting plate（4）It is in contact；Described anchorage（5）It is provided with acceleration transducer（7）And click resonator（8）, acceleration biography Sensor（7）With computer（10）Connection.
2. 2. the detecting system of prestress wire anchorage cable stretching power according to claim 1, it is characterised in that：Described adds Velocity sensor（7）With magnetic force suction base（71）Or rubber cement or gypsum mud are fixedly mounted on anchorage（5）End.
3. 3. the detecting system of prestress wire anchorage cable stretching power according to claim 1, it is characterised in that：Described adds Velocity sensor（7）Direction of vibration parallel to the steel strand wires after anchoring（1）Axis.
4. 4. the detecting system of prestress wire anchorage cable stretching power according to claim 1, it is characterised in that：After anchoring Steel strand wires（1）Provided with revealed section（6）Or it is not provided with revealed section（6）.
5. 5. the detecting system of prestress wire anchorage cable stretching power according to claim 1, it is characterised in that：Anchoring body （11）The material used is can make rock mass（2）, steel strand wires（1）, anchoring material（111）The material mutually consolidated.