Method for planarizing unevenness of the seabed

Abstract

At a location where unevenness 1000 is present, the condition of a seabed 200 is investigated in advance to examine the respective numbers of large filter units 51 and small filter units 52 to be used, and the position where the large filter units 51 and the small filter units 52 are to be installed. Based on the investigation result, the small filter units 52 are installed on the bottom of the unevenness 1000 . The large filter units 51 are installed on the upper surface formed by the installed small filter units 52 , and are leveled so that the upper surface formed by the installed large filter units 51 becomes flush with the seabed 200.

1 . A method for planarizing unevenness which is an uneven surface of a seabed, comprising the steps of
 installing a plurality of bag-shaped filter units, each containing predetermined block objects, on said unevenness; and   leveling said plurality of installed filter units so that an upper surface formed by said plurality of installed filter units becomes flush with said seabed.   
     
     
         2 . The method according to  claim 1 , wherein
 said step of installing said plurality of filter units includes the step of locating a position where said filter units are to be installed, by using a GPS.   
     
     
         3 . The method according to  claim 1 , wherein
 said filter units include a first filter unit having a first size and a second filter unit having a second size larger than said first size, and;   said step of installing said plurality of filter units includes the step of placing said second filter unit on said first filter unit.   
     
     
         4 . The method according to  claim 1 , wherein
 said filter units have a predetermined size and;   said step of installing said plurality of filter units includes the step of placing crushed stones on said unevenness before placing said filter units with the predetermined size.   
     
     
         5 . The method according to  claim 1 , wherein
 said filter units have a predetermined outer size and include a first filter unit having a first block objects with a first size and a second filter unit having a second block objects with a second size larger than said first size and;   said step of installing said plurality of filter units includes the step of placing said second filter unit on said first filter unit.   
     
     
         6 . The method according to  claim 1 , wherein
 said step of installing said plurality of filter units includes the step of placing crushed stones at the bottom of said unevenness before placing a plurality of said filter units.   
     
     
         7 . The method according to  claim 1 , wherein
 the volume of said filter units is equal or smaller than the volume of said unevenness.   
     
     
         8 . The method according to  claim 1 , wherein
 said filter unit includes a bag body and block objects, and;   when said filter unit is hung up, assuming that the height of said bag body from the closed portion to the bottom is H 1  and the height of a space without said block objects is H 2 , the amount of block objects obtained by (H 2 /H 1 )× 100  is 25-80%.   
     
     
         9 . The method according to  claim 8 , wherein
 the porosity of the knitted fabric of said bag body is 45% to 90%.