Soil Improvement Apparatus And Soil Improvement Method

Abstract

A soil improvement apparatus where an auger head is rotated even with small power and where an improvement material is extruded only in the horizontal direction. The soil improvement apparatus has soil compacting means that is constructed by inserting an auger in a tubular casing. The auger has a rotating shaft and a rotating tube that are coaxially arranged and rotate independently in the circumferential direction, an auger head attached to the lower end of the rotating shaft, and a screw provided on the outer periphery of the rotating tube. The auger head is constructed by arranging wedge-shaped auger blades, having recessed pressing sections, on the lower end of the rotating shaft projecting from the casing, and the auger blades are arranged in a radial pattern with the pressing sections facing the radial direction.

1 : A soil improvement apparatus comprising a soil consolidating means that includes a tubular casing and an auger that is inserted into the casing, said auger including a rotational shaft and a rotational tube that are disposed coaxially with each other and circumferentially rotated independently of each other, an auger head that is attached to a lower end of the rotational shaft, and a screw that extends around the outer circumference of rotational tube, wherein 
 said auger head includes plural wedge-shaped auger blades that each have a pressing part inwardly recessed and are disposed radially around a lower end of the rotational shaft with the pressing parts oriented in a radial direction, said lower end of the rotational shaft extending outwards from the casing.    
   
   
       2 : The soil improvement apparatus according to  claim 1 , wherein a plural number of the soil consolidating means are disposed adjacent to each other, with each of said soil consolidating means having said auger head provided therein.  
   
   
       3 : The soil improvement apparatus according to  claim 1 , wherein the auger head is rotated at such a low speed as to allow an improvement material to be repeatedly kneaded, wherein said improvement material is to be extruded outwards.  
   
   
       4 : The soil improvement apparatus according to  claim 1 , wherein the auger head is rotated by an electric motor that is controlled so that when the value of the electric current being variable depending on the magnitude of load applied reaches a given value, the electric motor is stopped.  
   
   
       5 : The soil improvement apparatus according to  claim 1 , further comprising a pressure measuring means that is combined with the soil consolidating means, and that includes a pipe to be embedded in soil, said pipe having a leading end portion and a main body separable from each other, a pressure sensitive element that is accommodated within the pipe so as to be exposed to the outside when the pipe is separated and is deformed upon receiving a given pressure, and a measuring instrument that measures, on the basis of the resultant deformation of the pressure sensitive element, a pressure applied to the pressure sensitive element.  
   
   
       6 : A soil improvement method comprising providing the soil improvement apparatus according to  claim 1  and extruding an improvement material into soft soil by the pressing parts of the auger blades, wherein said improvement material is made up of soil drilled out and a fastening material in filament form mixed into the soil.  
   
   
       7 : The soil improvement apparatus according to  claim 2 , wherein the auger head is rotated at such a low speed as to allow an improvement material to be repeatedly kneaded, wherein said improvement material is to be extruded outwards.  
   
   
       8 : The soil improvement apparatus according to  claim 2 , wherein the auger head is rotated by an electric motor that is controlled so that when the value of the electric current being variable depending on the magnitude of load applied reaches a given value, the electric motor is stopped.  
   
   
       9 : The soil improvement apparatus according to  claim 3 , wherein the auger head is rotated by an electric motor that is controlled so that when the value of the electric current being variable depending on the magnitude of load applied reaches a given value, the electric motor is stopped.  
   
   
       10 : The soil improvement apparatus according to  claim 2 , further comprising a pressure measuring means that is combined with the soil consolidating means, and that includes a pipe to be embedded in soil, said pipe having a leading end portion and a main body separable from each other, a pressure sensitive element that is accommodated within the pipe so as to be exposed to the outside when the pipe is separated and is deformed upon receiving a given pressure, and a measuring instrument that measures, on the basis of the resultant deformation of the pressure sensitive element, a pressure applied to the pressure sensitive element.  
   
   
       11 : The soil improvement apparatus according to  claim 3 , further comprising a pressure measuring means that is combined with the soil consolidating means, and that includes a pipe to be embedded in soil, said pipe having a leading end portion and a main body separable from each other, a pressure sensitive element that is accommodated within the pipe so as to be exposed to the outside when the pipe is separated and is deformed upon receiving a given pressure, and a measuring instrument that measures, on the basis of the resultant deformation of the pressure sensitive element, a pressure applied to the pressure sensitive element.  
   
   
       12 : The soil improvement apparatus according to  claim 4 , further comprising a pressure measuring means that is combined with the soil consolidating means, and that includes a pipe to be embedded in soil, said pipe having a leading end portion and a main body separable from each other, a pressure sensitive element that is accommodated within the pipe so as to be exposed to the outside when the pipe is separated and is deformed upon receiving a given pressure, and a measuring instrument that measures, on the basis of the resultant deformation of the pressure sensitive element, a pressure applied to the pressure sensitive element.  
   
   
       13 : The method of  claim 6 , wherein a plural number of the soil consolidating means are disposed adjacent to each other, with each of said soil consolidating means having said auger head provided therein.  
   
   
       14 : The method of  claim 6 , wherein the auger head is rotated at such a low speed as to allow an improvement material to be repeatedly kneaded, wherein said improvement material is to be extruded outwards.  
   
   
       15 : The method of  claim 6 , wherein the auger head is rotated by an electric motor that is controlled so that when the value of the electric current being variable depending on the magnitude of load applied reaches a given value, the electric motor is stopped.  
   
   
       16 : The method of  claim 6 , wherein said soil improvement apparatus further comprises a pressure measuring means that is combined with the soil consolidating means, and that includes a pipe to be embedded in soil, said pipe having a leading end portion and a main body separable from each other, a pressure sensitive element that is accommodated within the pipe so as to be exposed to the outside when the pipe is separated and is deformed upon receiving a given pressure, and a measuring instrument that measures, on the basis of the resultant deformation of the pressure sensitive element, a pressure applied to the pressure sensitive element.