Disclosure of Invention
In order to solve the technical problems, the invention provides a prestress monitoring anchor rod structure and a tensioning method, which prevent a stress meter from being damaged by torsion and ensure that the axial stress of the prestress anchor rod during tensioning meets the design requirements.
In order to achieve the purpose, the invention provides the following scheme:
the invention provides a prestress monitoring anchor rod structure, which comprises a prestress anchor rod, a stress meter, a grout stop plug, a nut, a guide assembly, a fixing assembly, a grouting assembly, an exhaust assembly and a plurality of centering brackets, the prestressed anchor comprises a first anchor section and a second anchor section, the first anchor section, the stress meter and the second anchor section are fixedly connected from front to back in sequence, the grout stop plug is fixedly sleeved on the first anchor rod section, a plurality of centering brackets are fixed on the second anchor rod section, the rear part of the second anchor rod section is sequentially sleeved with the guide assembly and the nut, the nut is in threaded connection with the second anchor rod section, the rear end of the second anchor rod section is used for being connected with one end of the fixing assembly, the other end of the fixing assembly is used for being anchored into the hole bedrock, and the grouting assembly and the exhaust assembly are arranged on one side of the prestressed anchor rod.
Preferably, the centering bracket comprises a plurality of centering rods fixed on the second anchor rod section, and the centering rods are uniformly arranged along the circumferential direction of the second anchor rod section.
Preferably, the number of the centering brackets is at least two, and the distance between two adjacent centering brackets is 2.5-3 m.
Preferably, the guide assembly comprises a guide pipe and a steel base plate fixed at one end of the guide pipe, and the guide pipe, the steel base plate and the nut are sequentially sleeved on the rear portion of the second anchor rod section from front to back.
Preferably, leveling mortar is arranged between the steel base plate and the orifice bedrock.
Preferably, the slip casting subassembly includes first slip casting pipe and second slip casting pipe, the exhaust subassembly includes first blast pipe and second blast pipe, first slip casting pipe with first blast pipe is run through forward by the back the end thick liquid stopper, the second slip casting pipe set up in second stock section rear portion one side, the second blast pipe set up in second stock section with stress meter one side.
Preferably, fixed subassembly includes first pin and second pin, first pin is used for being fixed in second stock section rear end, second pin one end is used for being fixed in on the first pin, the second pin other end is used for the anchor to go into in the drill way bedrock.
The invention also provides a tensioning method for monitoring the anchor rod structure by adopting the prestress, which comprises the following steps:
firstly, respectively fixing the first anchor rod section and the second anchor rod section at two ends of the stress meter, fixing the grout stop plug at the first anchor rod section, fixing the centering bracket at the second anchor rod section, and combining the grouting assembly and the exhaust assembly with the prestressed anchor rod;
secondly, inserting the prestressed anchor rod into the hole through manual or mechanical cooperation, wherein the front end of the grout stop plug is an anchoring section, the rear end of the grout stop plug is a free section, grouting is performed on the anchoring section through the grouting assembly, and the guiding assembly and the nut are installed after grouting of the anchoring section is completed;
thirdly, mounting the fixing assembly, welding one end of the fixing assembly with the rear end of the second anchor rod section, and anchoring the other end of the fixing assembly into the hole bedrock;
fourthly, after the strength of the anchoring section is over, tensioning the prestressed anchor rod;
step five, clamping a torque wrench on the nut, clockwise screwing, and screwing in stages until the last stage reaches a set value torque alarm value, and finishing tensioning;
monitoring a stress loss value 48 hours after tensioning locking is finished, judging that the stress loss value is qualified when the stress loss value is less than 10% of the tensioning value, and performing free-section grouting through the grouting assembly;
and seventhly, cutting off the fixing assembly, and sealing the anchor at the hole opening for protection.
Compared with the prior art, the invention has the following technical effects:
the invention provides a prestress monitoring anchor rod structure and a tensioning method.A prestress anchor rod comprises a first anchor rod section and a second anchor rod section, wherein the first anchor rod section, a stress meter and the second anchor rod section are sequentially and fixedly connected from front to back; the rear portion of second stock section is overlapped in proper order and is equipped with direction subassembly and nut, further carries out spacing between two parties to the second stock section through setting up the direction subassembly. The rear end of second stock section is arranged in being connected with the one end of fixed subassembly, and the other end of fixed subassembly is arranged in the anchor drill way bedrock, and fixed subassembly fixes the tip of prestressed anchorage pole, and then stress gauge receives the torsional damage when preventing to adopt torque wrench construction.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a prestress monitoring anchor rod structure and a tensioning method, which can prevent a stress meter from being damaged by torsion and ensure that the axial stress of the prestress anchor rod during tensioning meets the design requirement.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
As shown in fig. 1-6, the present embodiment provides a prestress monitoring anchor rod structure, including a prestressed anchor rod, a stress meter 3, a grout stop 4, a nut 8, a guiding component, a fixing component, a grouting component, an exhaust component and a plurality of centering brackets 5, the prestressed anchor rod includes a first anchor rod section 1 and a second anchor rod section 2, the first anchor rod section 1, the stress meter 3 and the second anchor rod section 2 are sequentially and fixedly connected from front to back, the grout stop 4 is fixedly sleeved on the first anchor rod section 1, specifically, the grout stop 4 is tied to the first anchor rod section 1. A plurality of centering support 5 is fixed in on second stock section 2, and centering support 5 can guarantee that prestressed anchorage pole free state or stretch-draw back are in the state of being placed in the middle basically, avoids producing the frictional force to the pore wall when stretch-draw to body of rod axial atress satisfies the design requirement when guaranteeing to stretch-draw. The rear portion of second stock section 2 is overlapped in proper order and is equipped with direction subassembly and nut 8, and nut 8 and 2 threaded connection of second stock section are spacing further between two parties to second stock section 2 through setting up the direction subassembly. The rear end of the second anchor rod section 2 is used for being connected with one end of a fixing assembly, the other end of the fixing assembly is used for anchoring into the orifice bedrock 16, the fixing assembly fixes the end of the prestressed anchor rod, and then the stress gauge 3 is prevented from being twisted and damaged when the torque wrench 17 is adopted for construction. The grouting assembly and the exhaust assembly are arranged on one side of the prestressed anchor rod.
As shown in fig. 2, the centering bracket 5 includes a plurality of centering rods 51 fixed to the second anchor segment 2, and the plurality of centering rods 51 are uniformly arranged along the circumferential direction of the second anchor segment 2. Specifically, the centering rods 51 are made of steel bars with the length of 5cm and the diameter of 22-25mm, the number of the centering rods 51 is three, and the centering rods 51 are welded on the second anchor rod section 2.
Specifically, the number of the centering brackets 5 is at least two, and the distance between two adjacent centering brackets 5 is 2.5-3 m.
As shown in fig. 4, two ends of the strain gauge 3 are respectively welded with the first anchor rod segment 1 and the second anchor rod segment 2, and the first anchor rod segment 1 and the second anchor rod segment 2 adopt hot-rolled ribbed steel bars with the diameter of 36 mm.
As shown in fig. 5, the guiding assembly comprises a guiding tube 6 and a steel pad plate 7 fixed at one end of the guiding tube 6, and the guiding tube 6, the steel pad plate 7 and the nut 8 are sequentially sleeved at the rear part of the second anchor rod section 2 from front to back.
Specifically, a leveling mortar 9 is arranged between the steel base plate 7 and the orifice bedrock 16, an outlet hole 10 penetrating through the leveling mortar 9 and the steel base plate 7 is further arranged, a monitoring cable led out by the stress meter 3 can penetrate through the outlet hole 10 to extend to the outside, and the monitoring cable is connected with a data acquisition instrument.
As shown in fig. 2 and 3, the grouting assembly comprises a first grouting pipe 11 and a second grouting pipe, the exhaust assembly comprises a first exhaust pipe 12 and a second exhaust pipe 13, the first grouting pipe 11 and the first exhaust pipe 12 penetrate through the grout stop plug 4 forwards after passing through, the second grouting pipe is arranged on one side of the rear portion of the second anchor rod section 2, the second exhaust pipe 13 is arranged on one side of the second anchor rod section 2 and the stress gauge 3, and the first grouting pipe 11, the second grouting pipe, the first exhaust pipe 12 and the second exhaust pipe 13 can extend to the outside through the outlet hole 10. Specifically, a first grouting pipe 11, a second grouting pipe, a first exhaust pipe 12 and a second exhaust pipe 13 are bound to the prestressed anchor.
As shown in fig. 5 and 6, the fixing assembly comprises a first stopper rod 14 and a second stopper rod 15, the first stopper rod 14 is used for being fixed at the rear end of the second anchor rod segment 2, one end of the second stopper rod 15 is used for being fixed on the first stopper rod 14, and the other end of the second stopper rod 15 is used for being anchored into the hole bedrock 16.
Specifically, the first stopper rod 14 and the second anchor rod segment 2 are perpendicular to each other and are welded to each other, and the second stopper rod 15 and the first stopper rod 14 are perpendicular to each other and are welded to each other.
The embodiment also provides a tensioning method for monitoring the anchor rod structure by adopting prestress, which comprises the following steps of:
firstly, respectively fixing a first anchor rod section 1 and a second anchor rod section 2 at two ends of a stress meter 3, fixing a grout stop plug 4 at the first anchor rod section 1, fixing a centering bracket 5 at the second anchor rod section 2, and combining a grouting assembly and an exhaust assembly with a prestressed anchor rod; specifically, the grout stop plug 4, the first grouting pipe 11, the first exhaust pipe 12, the second grouting pipe and the second exhaust pipe 13 are bound on the prestressed anchor rod, 15cm of threads are turned on the end part of the rear end of the second anchor rod section 2, and meanwhile, an assembly of the guide pipe 6 and the steel backing plate 7 is machined.
And step two, inserting the prestressed anchor rod into the hole through manual or mechanical cooperation, wherein the front end of the grout stop plug 4 is an anchoring section, and the rear end of the grout stop plug 4 is a free section, in the embodiment, the anchoring section is 2.5m, and the free section is 6.5 m. Carry out anchor section slip casting through first slip casting pipe 11, first exhaust pipe 12 exhausts at the slip casting in-process, anchor section slip casting is accomplished the back, carry out the installation of direction subassembly and nut 8, specifically, locate 2 backs in second anchor section with the 7 covers of stand pipe 6 and steel backing plate, pour mortar 9 of making level between steel backing plate 7 and drill way bedrock 16, scribble the butter layer on nut 8 and steel backing plate 7 during installation nut 8, reduce the stretch-draw resistance, nut 8 and 2 threaded connection in second anchor section. Specifically, drill way department is provided with the exit hole 10 that runs through leveling mortar 9 and steel backing plate 7, and first slip casting pipe 11, first blast pipe 12, second slip casting pipe and second blast pipe 13 all extend to the outside through exit hole 10, and simultaneously, the monitoring cable ligature of stressometer 3 is on second stock section 2, and extends the outside by exit hole 10, exposes about 50cm in drill way, utilizes data acquisition instrument data acquisition.
Step three, mounting the fixing component, welding one end of the fixing component with the rear end of the second anchor rod section 2, and anchoring the other end of the fixing component into the orifice bedrock 16; specifically, a first stop lever 14 is vertically welded at the rear end of the second anchor rod segment 2, one end of a second stop lever 15 is vertically welded at the lower end of the first stop lever 14, the other end of the second stop lever 15 is anchored in the hole bedrock 16, and the depth of the second stop lever 15 anchored in the hole bedrock 16 is 200 mm.
And step four, after the anchoring section and the leveling mortar 9 have the strength, preparing to stretch the prestressed anchor rod.
And fifthly, checking whether the components such as the first stop lever 14, the second stop lever 15, the nut 8, the guide pipe 6, the steel backing plate 7, the second grouting pipe and the second exhaust pipe 13 are complete, after checking, clamping a torque wrench 17 on the nut 8, clockwise screwing, and screwing in stages until the last stage reaches a set value torque alarm value, and finishing tensioning.
And step six, monitoring a stress loss value 48 hours after tensioning locking is finished, judging that the stress loss value is less than 10% of the tensioning value and is qualified, performing free section grouting through a second grouting pipe, and exhausting the second exhaust pipe 13 in the grouting process.
And seventhly, cutting off the fixed assembly, specifically, cutting off the first stop lever 14 and the second stop lever 15 by adopting a handheld grinder, sealing and protecting the anchor at the hole opening, then carrying out long-term data acquisition and monitoring, and feeding back the stress change condition in time.
The principle and the implementation mode of the present invention are explained by applying specific examples in the present specification, and the above descriptions of the examples are only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.