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    First, concrete strength testing
Concrete strength is the main indicator for evaluating its quality.
The basic method for concrete strength testing is to prefabricate the test block in the field for strength testing. The strength grade of concrete is divided by the cubic compressive strength (in N/mm 2 or MPa). The standard value of the compressive strength of the cube refers to a value of the 150 mm test piece produced and cured by the standard method, and the overall distribution of the compressive strength measured by the standard test method at 28 d. When other sizes of test pieces are required, they can be converted according to regulations.
Non-destructive testing methods can be used for completed concrete structures, including rebound method, ultrasonic pulse method, and ultrasonic rebound comprehensive method. In addition, micro-breakage detection techniques such as pull-out test methods can also be used.
The calculation method and conformity assessment of the test strength shall be carried out in accordance with the provisions of GB/T 50107 2010.
The basic method for concrete strength testing is to prefabricate the test block in the field for strength testing. The strength grade of concrete is divided by the cubic compressive strength (in N/mm 2 or MPa). The standard value of the compressive strength of the cube refers to a value of the 150 mm test piece produced and cured by the standard method, and the overall distribution of the compressive strength measured by the standard test method at 28 d. When other sizes of test pieces are required, they can be converted according to regulations.
Non-destructive testing methods can be used for completed concrete structures, including rebound method, ultrasonic pulse method, and ultrasonic rebound comprehensive method. In addition, micro-breakage detection techniques such as pull-out test methods can also be used.
The calculation method and conformity assessment of the test strength shall be carried out in accordance with the provisions of GB/T 50107 2010.
Second, the anchor construction project
1. Anchor pullout detection
The bolt (anchor) pullout resistance refers to its ability to resist pulling out of the rock mass in units of kN or N. The pull-out force is an important performance of the anchor (anchor) support capacity and an important indicator of its construction quality. A conventional method of detecting the pullout resistance of a bolt or anchor is to perform a tensile test using a bolt dynamometer.
2. Between the installation of the bolts, if the bolts are not covered by the shotcrete, they can be measured directly by the ruler. The obtained data is used as the basis for evaluating the quality of the bolt arrangement. If the anchor is covered by concrete, a bolt detector is required.
3. Tray according to Quality Inspection "coal mine roadway construction quality acceptance)) GB 50213-2010 and" Rock bolt and shotcrete engineering specification)) of the predetermined GB 50086- ~ 2015, requires the installation of bolt pallet Firm, adherent to the wall or tight to the rock face. The torque wrench test meets the requirements of 100 N. m. For the inspection of the anchor pallets that are not covered by the shotcrete, the on-site pulling and observation can be directly carried out; for the bolts that have been covered by the concrete, the construction inspection records on the inspection points are checked according to the concealed works. The quality inspection records of the bolt pallet installation are completed by the team in a row; in the middle or completion acceptance, the inspection requirements of the shaft are not more than 20m and the roadway is not more than 25m. The installation quality of the previous row of pallets is checked at each checkpoint.
4. Bolt hole depth, angle detection Bolt hole depth and angle are also important indicators to reflect the quality of bolt support. At present, it is still tested according to the method of concealed engineering.
The installation quality of the bolt includes the installation quality of the anchor pallet, the spacing between the anchors, the depth of the anchor hole, the angle, and the exposed length of the bolt.
2. Between the installation of the bolts, if the bolts are not covered by the shotcrete, they can be measured directly by the ruler. The obtained data is used as the basis for evaluating the quality of the bolt arrangement. If the anchor is covered by concrete, a bolt detector is required.
3. Tray according to Quality Inspection "coal mine roadway construction quality acceptance)) GB 50213-2010 and" Rock bolt and shotcrete engineering specification)) of the predetermined GB 50086- ~ 2015, requires the installation of bolt pallet Firm, adherent to the wall or tight to the rock face. The torque wrench test meets the requirements of 100 N. m. For the inspection of the anchor pallets that are not covered by the shotcrete, the on-site pulling and observation can be directly carried out; for the bolts that have been covered by the concrete, the construction inspection records on the inspection points are checked according to the concealed works. The quality inspection records of the bolt pallet installation are completed by the team in a row; in the middle or completion acceptance, the inspection requirements of the shaft are not more than 20m and the roadway is not more than 25m. The installation quality of the previous row of pallets is checked at each checkpoint.
4. Bolt hole depth, angle detection Bolt hole depth and angle are also important indicators to reflect the quality of bolt support. At present, it is still tested according to the method of concealed engineering.
The installation quality of the bolt includes the installation quality of the anchor pallet, the spacing between the anchors, the depth of the anchor hole, the angle, and the exposed length of the bolt.
Third, shotcrete construction project
1. Shotcrete strength testing
(1) Shotcrete strength test evaluation of shotcrete (sometimes referred to as shotcrete), its strength can be the same as ordinary sea concrete, using standard test methods to obtain 28d age compressive strength, and by comparing the same batch of test groups The average value and the lowest value are compared with the design specifications for conformity assessment. The procedure specifies the specific calculation method.
Shotcrete can also be determined by point load and pull-out test methods.
(2) Sampling
The shotcrete strength test specimens are subjected to on-site sampling methods, including spray slab method or drill method and chisel cutting method.
1) Drilling method. A shotcrete core with a diameter of 50 mm and a length of more than 55 mm was drilled on the actual structure that had been cured for 28 days, and the test was carried out after cutting at both ends.
2) Sampling by spraying the large plate method. Use 350mmX 450mmX 120mm mold (short side open), placed on the wall of the shotcrete work site; after normal operation, spray from bottom to top into the mold layer by layer, after 1d, release the mold under standard conditions for 7d, processed into Standard test pieces were tested after 28 days of curing.
3) Chiseling method. On the concrete structure that has been sprayed and cured for 14 days, a tear concrete block with a length of 350 mm and a width of 150 mm is drilled. It can be processed into a 100mmX 100mmX 100mm cube test piece and cured to 28d for pressure test on the press.
The number of test groups for each batch of tear-throated concrete varies according to the nature of the project.
2. Shotcrete thickness Shotcrete thickness detection commonly used needle detection method, perforation ruler or coring method.
3. Shotcrete engineering specification size
(1) For the detection of the size of the section of the Kunming Consolidation Engineering, there are mainly the following methods: hanging line measuring method, laser ranging method, ultrasonic ranging method and so on. Shotcrete smooth dense surface, and a ruler with measurements of 1m feeler gauge, the measuring point within the range of 1m 2 irregularities not more than 50mm.
(2) The depth of the shotcrete foundation is generally measured by the ruler method.
4. perception of the quality of the concrete anchor spray anchor spray works to detect the perception of quality testing including leak spray from the drum phenomenon yuan is still expanding cracks or endanger the safety of use; in line with the amount of leaking water standards; reinforcing mesh (metal mesh) shall be exposed The molding is good, the profile of the section meets the design requirements, and the wall is straight and the arch is smooth.
(1) Shotcrete strength test evaluation of shotcrete (sometimes referred to as shotcrete), its strength can be the same as ordinary sea concrete, using standard test methods to obtain 28d age compressive strength, and by comparing the same batch of test groups The average value and the lowest value are compared with the design specifications for conformity assessment. The procedure specifies the specific calculation method.
Shotcrete can also be determined by point load and pull-out test methods.
(2) Sampling
The shotcrete strength test specimens are subjected to on-site sampling methods, including spray slab method or drill method and chisel cutting method.
1) Drilling method. A shotcrete core with a diameter of 50 mm and a length of more than 55 mm was drilled on the actual structure that had been cured for 28 days, and the test was carried out after cutting at both ends.
2) Sampling by spraying the large plate method. Use 350mmX 450mmX 120mm mold (short side open), placed on the wall of the shotcrete work site; after normal operation, spray from bottom to top into the mold layer by layer, after 1d, release the mold under standard conditions for 7d, processed into Standard test pieces were tested after 28 days of curing.
3) Chiseling method. On the concrete structure that has been sprayed and cured for 14 days, a tear concrete block with a length of 350 mm and a width of 150 mm is drilled. It can be processed into a 100mmX 100mmX 100mm cube test piece and cured to 28d for pressure test on the press.
The number of test groups for each batch of tear-throated concrete varies according to the nature of the project.
2. Shotcrete thickness Shotcrete thickness detection commonly used needle detection method, perforation ruler or coring method.
3. Shotcrete engineering specification size
(1) For the detection of the size of the section of the Kunming Consolidation Engineering, there are mainly the following methods: hanging line measuring method, laser ranging method, ultrasonic ranging method and so on. Shotcrete smooth dense surface, and a ruler with measurements of 1m feeler gauge, the measuring point within the range of 1m 2 irregularities not more than 50mm.
(2) The depth of the shotcrete foundation is generally measured by the ruler method.
4. perception of the quality of the concrete anchor spray anchor spray works to detect the perception of quality testing including leak spray from the drum phenomenon yuan is still expanding cracks or endanger the safety of use; in line with the amount of leaking water standards; reinforcing mesh (metal mesh) shall be exposed The molding is good, the profile of the section meets the design requirements, and the wall is straight and the arch is smooth.
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