Non-destructive detection method and device of effective anchorage depth of full-length bonding anchor

Abstract

The present invention relates to a method and an apparatus for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt, which are applicable in geotechnical engineering. The method provided by the invention is for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt; the method is convenient to operate, non-destructive to an anchor bolt, and capable of testing an anchorage length of the anchor bolt. The present invention further provides an apparatus for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt. The apparatus has a simple structure, is convenient to install, and is capable of measuring an anchorage length of an anchor bolt without damaging the anchor bolt.

What is claimed is: 
     
         1 . A method for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt, comprising:
 impacting an end of an extended section of an anchor bolt for multiple times with different amplitudes, so as to enable the anchor bolt to generate different accelerations;   acquiring accelerations at different depths of the anchor bolt by using several accelerometers that are disposed at the different depths along the anchor bolt; and   observing acceleration values obtained by the accelerometer, wherein if an acceleration value is stable, it is determined that the anchor bolt of a position at which a corresponding accelerometer is located is closely adhered to surrounding rock, and the position represents an effective anchorage length of the anchor bolt, and otherwise, if an acceleration value is noticeably vibrated, it is determined that adhesion of a position at which a corresponding accelerometer is located is insufficiently close, the anchor bolt is loose, and the position fails to represent an effective anchorage length of the anchor bolt.   
     
     
         2 . The method for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt according to  claim 1 , comprising steps as follows:
 S 01 : installing the anchor bolt, comprising: installing the accelerometers on the anchor bolt, placing the anchor bolt at a center of a borehole, leading out transmission cables connected to the accelerometers, and fastening the anchor bolt to the borehole by using an adhesive material;   S 02 : installing an acceleration excitation apparatus and an acceleration monitoring apparatus, comprising: installing an acceleration excitation apparatus and an acceleration monitoring apparatus at the extended section of the anchor bolt after the adhesive material in the borehole reaches designed strength, and connecting the acceleration monitoring apparatus to the accelerometers by using the transmission cables; and   S 03 : testing an effective anchorage length, comprising: axially applying a force to the anchor bolt by using the acceleration excitation apparatus; observing, by the acceleration monitoring apparatus, the acceleration values obtained by the accelerometers, wherein if the anchor bolt is closely adhered to the surrounding rock, and an acceleration value is stable and is small, the position represents an effective anchorage length of the anchor bolt, and if an acceleration value is noticeably vibrated, it is indicated that the anchor bolt at the position is loose, and the position fails to represent an effective anchorage length of the anchor bolt.   
     
     
         3 . The method for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt according to  claim 2 , wherein the force axially applied by the acceleration excitation apparatus to the anchor bolt in step S 03  is  10  KN- 50  KN, and the force is gradually increased with an increment of  10  KN each time. 
     
     
         4 . An apparatus for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt, configured to test an anchorage length of a fully grouted anchor bolt, wherein the anchor bolt is placed in a borehole that is fully filled with an adhesive material; the anchor bolt is fastened to a rock wall by using a steel plate at an opening of the borehole; an acceleration excitation apparatus that can apply an axial vibration force to the anchor bolt is installed at an extended section of the anchor bolt; several accelerometers are installed, along an axial direction of the anchor bolt, on the anchor bolt in the borehole; and the accelerometers are electrically connected to an acceleration monitoring apparatus outside the borehole by using transmission cables. 
     
     
         5 . The apparatus for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt according to  claim 4 , wherein the acceleration excitation apparatus and the acceleration monitoring apparatus are installed in a sleeve, and are installed at an end of the extended section of the anchor bolt by using the sleeve;
 and the acceleration excitation apparatus is securely connected to the anchor bolt by using a connection rod and a loading ring.   
     
     
         6 . The apparatus for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt according to  claim 5 , wherein a compression type dynamometer used to measure a vibration force of the acceleration excitation apparatus is disposed between the steel plate and the sleeve. 
     
     
         7 . The apparatus for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt according to  claim 6 , wherein a plate is disposed between one end of the compression type dynamometer and the steel plate, and a plate is disposed between the other end of the compression type dynamometer and the sleeve. 
     
     
         8 . The apparatus for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt according to  claim 4 , wherein the sleeve is connected to a top end of a vertical stabilizer bar in a manner of capable of axially and horizontally moving along the anchor bolt, and the other end of the stabilizer bar is fastened to ground. 
     
     
         9 . The apparatus for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt according to  claim 4 , wherein an electromagnetic vibrator is used as the acceleration excitation apparatus, and an acceleration vibration pickup is used as the acceleration monitoring apparatus.