EP0849404A1

EP0849404A1 - Manhole surface repairing method

Info

Publication number: EP0849404A1
Application number: EP96309422A
Authority: EP
Inventors: Shinya Tokai Rubber Industries LTD. Uda; Okusa Tokai Rubber Industries LTD. Ishihara; Isao Tokai Rubber Industries LTD. Natsubori; Shuichi Tokai Chemical Ind. LTD. Takahashi; Tokai Chemical Ind. LTD. Mizukami Isao; Mitsuyoshi Tokai Chemical Ind. LTD. Kondo; Katsumi Kansei Kogyo Co. LTD. Nakamura; Hisashi Kansei Kogyo Co. LTD. Niwa; Yoshiki Nisso Shoji Co. LTD. Kato; Shuji Nisso Shoji Co. LTD. Miura; Yutaka c/o Nisso Petrochemical Ind. Co. LTD Tano
Original assignee: Tokai Chemical Industries Ltd; Sumitomo Riko Co Ltd; Kansei Co; Nisso Shoji Co Ltd
Current assignee: Tokai Chemical Industries Ltd; Sumitomo Riko Co Ltd; Kansei Co; Nisso Shoji Co Ltd
Priority date: 1996-12-20
Filing date: 1996-12-20
Publication date: 1998-06-24

Abstract

Cylindrical manhole repairing materials (1,3) made of fiber reinforced unsaturated polyester are inserted into a manhole and laid on each other to cover a vertical surface section (6) of an inner surface (2) of a manhole. Then, a manhole repairing material (9) made of fiber reinforced unsaturated polyester is inserted into the manhole and laid on upper one (3) of the cylindrical manhole repairing materials to cover an inclined surface section (8) of the inner surface of the manhole. Concurrently, a small gap (89) is defined between the inner surface of the manhole and the manhole repairing materials. The gap is charged therein with a cold setting epoxy resin (115), which is cured to form a lining layer.

Description

BACKGROUND OF THE INVENTION

This invention relates to a manhole surface repairing method, and more particularly to a method for repairing an inner surface of a manhole structure by lining, and a manhole repairing material for forming a lining layer, a closing member for preventing leakage of an impregnating material for lining and an expansion equipment for expanding a manhole repairing material which are suitable for use for the manhole surface repairing method.

A manhole structure (hereinafter also referred to as "manhole") is generally constructed of concrete, resulting in an inner surface thereof being subject to corrosion by hydrogen sulfide produced in an underground pipe such as a sewage pipe and/or sulfur oxides contained in rainwater over a long period of time. Also, the manhole structure is typically laid under a public road, so that cracks tend to occur in the inner surface of the manhole due to vibration applied thereto from vehicles traveling on the road. Such corrosion and cracks occurring on the inner surface of the manhole as described above cause ground water to enter an underground pipe such as a sewage pipe. Penetration of ground water into the sewage pipe increases the amount of sewage, leading to an increase in the number of steps in sewage disposal. Also, further advance of the corrosion and cracks may lead to collapse or cave-in of the manhole structure. Thus, it is required to carry out repairing and/or maintenance of the inner surface of the manhole structure timely.

A conventional method for repairing the inner surface of the manhole structure is generally practiced by securing a manhole repairing material of a cylindrical shape to the inner surface of the manhole, as disclosed in, for example. Japanese Patent Application Laid-Open Publications Nos. 29526/1989, 43623/1989 and 198325/1989. Alternatively, a manhole surface repairing method constructed so as to spray liquid resin containing a ceramic material, liquid hard urethane resin or the like onto the inner surface of the manhole to form a lining layer thereon is likewise employed for this purpose.

Formation of the lining layer or repairing material on the inner surface of the manhole under conditions that the inner surface is substantially subject to severe corrosion or cracks leads to a disadvantage that the lining layer or repairing material is rugged due to the corrosion or cracks, to thereby fail in satisfactory repairing of the inner surface. Also, spraying of the liquid resin onto the inner surface of the manhole for forming the lining layer thereon fails to satisfactorily apply the resin to a portion of the inner surface through which ground water enters the manhole, to thereby often cause the lining layer to be peeled off therefrom.

In order to avoid such a problem, a pretreatment is required wherein the inner surface is cleaned by means of high-pressure water and then a water-leakage portion of the inner surface is sealed with quick-setting cement, followed by repairing of roughness on the inner surface by means of mortar to smooth the inner surface. Unfortunately, a long period of time as long as several days is generally required for completion of the pretreatment, leading to a deterioration in operational efficiency and a traffic trouble such as a traffic jam, roadblocking or the like.

Additional manhole repairing techniques are disclosed in Japanese Patent Application Laid-Open Publication No. 301238/1993, wherein a flexible manhole repairing material including an upper section, a peripheral section and a bottom section is used. Then, cement milk is charged or cast into a relatively large gap between the manhole repairing material and an inner surface of a manhole structure and than cured. However, the flexible manhole repairing material tends to cause roughness or ruggedness to be formed on an inner surface thereof, to thereby fail to provide a satisfactory lining layer.

SUMMARY OF THE INVENTION

The present invention has been made in view of the foregoing disadvantage of the prior art.

Accordingly, it is an object of the present invention to provide a manhole surface repairing method which is capable of providing a lining layer which exhibits a sufficient repairing function and has an inner surface smoothly finished.

It is another object of the present invention to provide a manhole repairing material which is capable of forming a satisfactory lining layer on an inner surface of a manhole structure.

It is a further object of the present invention to provide a closing member which is capable of effectively preventing leakage of an impregnating material for lining charged into a gap between a manhole repairing material and an inner surface of a manhole structure.

It is still another object of the present invention to provide an expansion equipment which is capable of effectively expanding, in a manhole structure, a manhole repairing material used for forming a lining layer on an inner surface of the manhole structure.

In accordance with one aspect of the present invention, a method for repairing an inner surface of a manhole structure by lining is provided. The method comprises the steps of arranging a thin-wall repairing material structure in the manhole so as to cover or lay the inner surface of the manhole with a gap being defined between the repairing material structure and the inner surface of the manhole and charging the gap with a liquid cold setting impregnating material for lining, followed by curing of the impregnating material. Typically, the repairing material structure is formed so as to have rigidity sufficient to exhibit self-supporting characteristics and formation of a lining layer is not practiced while keeping the repairing material structure pressed directly against the inner surface of the manhole, so that the repairing material structure is kept from being formed with undulations corresponding to roughness on the inner surface of the manhole. The cold setting impregnating material charged between the inner surface of the manhole and the repairing material structure fully enters a corroded portion and cracks of the inner surface, to thereby exhibit sufficient waterstop and reinforcing functions. Thus, cleaning of the inner surface using high-pressure water or a rotary brush is merely required as a pretreatment therefor.

In general, the manhole structure is so constructed that an entrance thereof has a diameter smaller than that of an intermediate or lower section thereof. Thus, it is required that the repairing material structure is inserted into the manhole while being deformed or shrunk into a shape sufficient to permit it to pass through the entrance of the manhole. Concurrently, the repairing material structure is required to exhibit rigidity or stiffness to a degree. In order to meet both requirements, in the present invention, the repairing material structure includes a cylindrical body made of a plastic material and provided with one vertically extending cut, to thereby be expandable. Such construction permits the repairing material structure to be not only readily inserted into the manhole but released from overlap thereof in the manhole, resulting in the structure being expanded to a degree sufficient to satisfactorily cover the inner surface of the manhole.

The manhole is typically formed at an upper portion thereof into a frust-conical shape, to thereby be gradually reduced in diameter toward an entrance thereof. Thus, in order to form a lining layer on the whole inner surface of the manhole, it is required that the repairing material structure includes both a frust-conical section and a cylindrical section. Integral formation of the frust-conical section and cylindrical section renders reduction in diameter or shrinkage of the repairing material structure often difficult. Thus, it is desired that the frust-conical and cylindrical sections are formed separately from each other and the cylindrical section is first inserted into the manhole while being shrunk, followed by insertion of the frust-conical section into the manhole while being shrunk. The frust-conical section is generally carried on an upper end of the cylindrical section. In this instance, the cold setting impregnating material is charged outside the cylindrical section after arrangement thereof in the manhole and then the frust-conical section is arranged in the manhole, followed by charging of the impregnating material outside the frust-conical section. However, it is generally carried out that after arrangement of the cylindrical section and frust-conical sections in the manhole, the impregnating material is charged outside both sections.

More specifically, the method of the present invention comprises the steps of providing a plurality of thin-wall cylindrical repairing materials formed of a plastic substance so as to cover a vertical surface section of an inner surface of a manhole and each provided with one vertically extending cut and a thin-wall cylindrical repairing material formed of a plastic substance so as to cover an inclined surface section of the inner surface of the manhole and provided with one vertically extending cut, inserting the repairing materials into the manhole while reducing a diameter of the repairing materials to overlap both ends thereof defined at the cut of each of said repairing materials each other and laying the repairing materials on each other by fitting, expanding the repairing materials during or after the laying by fitting, to thereby lay or cover the inner surface of the manhole with the repairing materials with a gap being defined between the repairing materials and the inner surface of the manhole, and charging a liquid cold setting impregnating material in the gap between the inner surface of the manhole and the repairing materials and curing the impregnating material. The vertical surface section of the inner surface of the manhole is generally formed into a relatively increased height, therefore, it is substantially difficult to cover the vertical surface section with a single repairing material of a large height. Also, arrangement of such a single repairing material renders uniform expansion Of the whole repairing material substantially difficult. In order to minimize the problem, an approach that the repairing material is first expanded at an upper end thereof and then expanded at a lower end thereof would be considered. However, such gradual expansion of the repairing material increased in height tends to lead to distortion or deformation of the material. Overlaying of the vertical surface section with the plural repairing materials laid on each other which is carried out in the present invention permits the repairing materials to be uniformly expanded either concurrently or successively without causing distortion or deformation of the materials. The repairing material arranged for covering the inclined surface section of the inner surface of the manhole as desired includes a frust-conical section and a short cylindrical section formed into a length or height reduced sufficiently so as not to interfere with an overlap at a lower end of the frust-conical section. The short cylindrical section is put or laid on an upper end of the repairing material for covering the vertical surface section and preferably stackedly fitted in the upper end of an increased diameter. Laying of the repairing materials on each other is carried out by fitting between the materials. This may be readily and stably accomplished using a suitable fitting means. In a preferred embodiment of the present invention, one of a lower end of upper one of each adjacent two of the repairing materials and an upper end of lower one thereof is formed into a diameter larger than the other, wherein laying of the repairing materials on each other is carried out by fitting between the lower end and the upper end. Such construction prevents any step from being formed between the repairing materials.

Sealing of the vertically extending cut after the repairing material is expanded in the manhole may be carried out by means of butt members arranged at the above-described both ends of the repairing material defined at the cut so as to be opposite to each other in a peripheral direction thereof. In this instance, both ends are preferably overlapped. In a preferred embodiment of the present invention, the two ends are formed into inner diameters different from each other, resulting in prevent any step from being formed at the overlap.

The repairing material is generally formed into a shape corresponding to that of the inner surface of the manhole. The inner surface of the manhole is formed into a suitable cross-sectional shape such as a circle, a rectangle or the like. Thus, the term "cylindrical" or "cylinder" used herein indicates a circular-shape, as well as a non-circular shape. Also, the term "expansion" means outward expansion or enlargement.

In general, it is considerably difficult to release the overlap of the repairing material to define a uniform gap between the inner surface of the manhole and the repairing material. In view of such difficulty, in a preferred embodiment of the present invention, the repairing material is integrally provided thereon with a plurality of vertically extending projections for gap formation in a manner to be distributed in a peripheral direction thereof or a plurality of small projections for gap formation, wherein the repairing material is arranged in the manhole while pressing the projections against the inner surface of the manhole. The vertically extending projections may be arranged so as to vertically extend in a manner to be either continuous or intermittent as desired. The projections each may be formed on an outer end thereof with any corrugation or recess, to thereby facilitate passage of the cold setting impregnating material between the projections and the inner surface of the manhole. The projections are gonerally formed into a height corresponding to the gap to be formed. Formation of the projections is carried out during molding of the repairing material and generally causes an inner surface of the projections to be recessed. This minimizes an increase in weight of the repairing material.

The cold setting impregnating material for lining is generally inexpensive and exhibits satisfactory adhesive properties and is preferably selected from the group consisting of epoxy resin, acrylic resin and unsaturated polyester resin. Alternatively, water glass or cement milk may be suitably used as the impregnating material. Plastic materials for the repairing material include thermoplastic materials such as polyethylene, polypropylene, vinyl chloride, polyamide and the like and thermosetting plastic materials such as unsaturated polyester, acrylic resin, epoxy resin and the like. Especially, fiber reinforced plastic exhibiting increased adhesive properties with respect to resin, in particular, fiber reinforced unsaturated polyester is effectively used.

The repairing material is formed so as to exhibit a modulus in flexure between 100 kg/mm² and 1500 kg/mm². The modulus in flexure below 100 kg/mm² causes the repairing material to tend to be substantially inwardly curved by its own gravity and a pressure of the impregnating material and undulate depending on roughness of the inner surface of the manhole structure. The modulus above 1500 kg/mm² causes deformation of the repairing material required for insertion thereof into the manhole to be highly hard. The gap between the inner surface of the manhole and the repairing material is defined to be between 2 mm and 10 mm. The gap below 2 mm renders charging of the impregnating material difficult, causes air trapping therein and fails to permit the impregnating material to be spread to a lower end of the gap. The gap above 10 mm leads to waste of the impregnating material and tends to cause excessive shrinkage of the impregnating material during curing thereof, resulting in undulation of the repairing material. The cold setting impregnating material for lining is preferably 3000 cSt in kinematic viscosity at 25°C. The kinematic viscosity above 3000 cSt renders charging of the impregnating material into the gap difficult, causes air trapping in the gap and fails to permit the impregnating material to be spread to a lower end of the gap. Also, if the viscosity approaches 3000 cSt even when the viscosity is below 3000 cSt, air trapping often occurs depending on environmental conditions. Thus, the viscosity is preferably reduced. In this respect, charging of the impregnating material reduced in viscosity into the gap at a stretch tends to cause leakage of the impregnating material from the lower end of the repairing material. In order to eliminate the problem, the cold setting impregnating material for lining may be charged and cured after a liquid curable waterstop material is charged in the gap between the inner surface of the manhole and the repairing material and cured. Liquid rubber such as liquid urethane resin, polybutadiene or the like may be used as the liquid curable waterstop material; however, epoxy resin, acrylic resin or unsaturated polyester resin as in the cold setting impregnating material may be conveniently used for this purpose. Also, in order to further prevent the leakage, the repairing material is preferably provided et the lower end thereof with a sealing material to ensure tight sealing between the lower end of the repairing material and a bottom surface of the manhole. Water-cured epoxy resin, moisture-cured silicone, mortar or the like may be used as the sealing material. In a preferred embodiment of the present invention, the repairing material arranged in the manhole is provided at the lower end thereof with the sealing material and then charging of the cold setting impregnating material or curable waters top material is carried out, so that liquid leakage from the lower end of the repairing material structure is more effectively prevented. In this instance, the sealing material may be typically applied to both an inside of the lower and of the repairing material and the bottom surface of the manhole.

In general, the gap between the repairing material and the inner surface of the manhole is formed into a reduced width, so that a non-charged region may possibly be formed in the gap even when the charging operation is carefully executed. When the repairing material is rendered transparent or semi-transparent so as to permit charging of the impregnating material to be visually observed, the charging operation may be efficiently and satisfactorily accomplished. Also, when the charging operation takes place in several times, the impregnating material may be accurately charged into a desired height.

The bottom surface of the manhole is typically formed in a manner to be downwardly inclined from both sides thereof toward a water channel formed on the bottom surface of the manhole so as to extend through a center of the bottom surface. Thus, the repairing material is preferably formed at the lower end thereof into a shape corresponding to undulation of the bottom surface of the manhole, to thereby ensure stable arrangement of the repairing material in the manhole and prevent liquid leakage from the lower end of the repairing material. More specifically, the lower end of the repairing material is preferably supported on the bottom surface of the manhole entirely or substantially entirely or through three or four points. Also, the inner surface of the manhole is provided at a lower portion thereof with sewage pipe openings, so that it is required to close each of the openings with a closing member in order to prevent leakage of the impregnating material to the opening. Similarly, it is also required to prevent leakage of the impregnating material to the water channel. In a preferred embodiment of the present invention, the closing members each include a rear plate formed so as to be curved in correspondence to a portion of the inner surface of the manhole positioned at the sewage pipe opening and a support bottom formed so as to inwardly extend from the rear plate, as well as a front plate arranged inside the support bottom so as to define a receiving groove of a reduced width between the front plate and the rear plate. The closing member is so arranged that the support bottom extends across the water channel. The repairing material is supported at the lower end thereof on the support bottom. Tight sealing is established between the repairing material and the support bottom, to thereby further prevent the liquid leakage. Also, arrangement of the lower end of the repairing material in the receiving groove effectively provides sufficient sealing between the repairing material and the closing member and ensures stable supporting of the repairing material on the bottom surface of the manhole.

The cylindrical repairing material may be kept expanded by manually expanding the repairing material and fixing the vertically extending cut by means of an adhesive tape. However, this requires careful operation and the adhesive tape often fails to resist a pressure of the cold setting impregnating material. In view of the problem, in accordance with another aspect of the present invention, an expansion equipment is provided for outwardly forcing an inner surface of the repairing material to expand the repairing material. The expansion equipment includes a ring formed with one cut, resulting In being provided at the cut with both ends which overlap each other and an adjustment mechanism for adjusting a width of overlap between both ends to fix both ends.

In a preferred embodiment of the present invention, the casing member is formed into a sideways U-shape, resulting in including an upper wall, a lower wall and a connection wall. The casing member is fixed to the one end of the ring while positioning the connection wall inside and the connection wall is provided thereon with a stopper which is contacted with the pinion to lock it. The connection wall may be formed with internal threads and the stopper may be formed with external threads which are threadedly inserted into the internal threads and contacted at a distal end thereof with the pinion.

BRIEF DESCRIPTION Of THE DRAWINGS

These and other objects and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings; wherein:

Fig. 1 is an exploded perspective view showing manhole repairing materials and closing members each constructed according to the present invention;

Fig. 2 is a partially cutaway schematic perspective view showing a manhole structure;

Fig. 3 is a vertical sectional view showing a manhole structure in which closing members are arranged;

Fig. 4 is a fragmentary sectional view showing arrangement of a closing member in a manhole;

Fig. 5 is a vertical sectional view showing a manhole structure in which a manhole repairing material is arranged;

Fig. 6 is a fragmentary vertical sectional view showing a manhole structure wherein a manhole repairing material is arranged while being forcedly pressed against an inner surface of the manhole structure;

Fig. 7 is a fragmentary vertical sectional view showing a sealing structure formed between an lower end of a manhole repairing member and a closing member;

Fig. 8 is a fragmentary vertical sectional view showing a sealing structure formed between a lower end of a manhole repairing member and a bottom surface of a manhole structure;

Fig. 9 is a vertical sectional view showing a manhole structure in which all required manhole repairing materials are arranged in a manner to be forcedly pressed against an inner surface of the manhole structure while being laid on each other;

Fig. 10 is a fragmentary vertical sectional view showing a manhole structure in which an uppermost manhole repairing material is arranged while forcedly pressed against an inner surface of the manhole structure;

Fig. 11 is a perspective view showing an expansion equipment according to the present invention;

Fig. 12 is a vertical sectional view showing an adjustment mechanism for the expansion equipment shown in Fig. 11;

Fig. 13 is a vertical sectional view showing a suspension ring member for the expansion equipment shown in Fig. 11;

Fig. 14 is a vertical sectional view showing arrangement of manhole repairing materials laid on each other by fitting and an adhesive layer;

Fig. 15 is a plan view showing an adhesive layer arranged at a cut of a manhole repairing material;

Fig. 16 is a vertical sectional view showing a manhole structure which is charged with a cold setting impregnating material for lining;

Fig. 17 is a vertical sectional view showing a manhole structure of which repairing operation is completed;

Fig. 18 is a fragmentary vertical sectional view showing curing of a cold setting impregnating material for lining; and

Fig. 19 is a perspective view showing another embodiment of a manhole repairing material according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, the present invention will be described hereinafter with reference to the accompanying drawings.

Referring first to Fig. 1, manhole repairing materials and closing members each constructed according to the present invention is illustrated. In Fig. 1,

reference numerals

1 and 3 each designate a manhole repairing material made of a plastic material into a cylindrical body and formed into a thickness of about 2.0 mm. The

manhole repairing materials

1 and 3 are arranged so as to cover a vertical surface section 6 of an inner surface 2 of a manhole structure while being laid or superposed on each other, as shown in Fig. 3. Reference numeral 9 likewise designates a manhole repairing material made of a plastic material and formed into a thickness of about 2 mm. The manhole repairing material 9 includes a frust-conical section 5 provided with an upper end thereof with a cylindrical portion 4 and constituting an upper part of the manhole repairing material 9 and a short cylindrical section 7 constituting a lower part of the material 9. The manhole repairing material 9 is put on the manhole repairing material 3 to cover an inclined surface section 8 of the inner surface 2 of the manhole, as shown in Fig. 3. The

manhole repairing materials

1, 3 and 9 are provided with vertical extending

cuts

11, 13 and 15, resulting in having both ends 171 and 173, 191 and 193, and 211 and 213 defined with the

cuts

11, 13 and 15 being interposed therebetween, respectively. Both ends 171 and 173, 191 and 193, and 211 and 213 are arranged so as to overlap each other, so that the ends 171, 191 and 211 are positioned inside the

ends

173, 193 and 213, respectively. In Fig. 1, the

manhole repairing materials

1, 3 and 9 are kept expanded. The outer ends 173, 193 and 213 each are formed so as to outwardly expand by a width of about 100 mm in a circumferential direction of the manhole repairing material. The outer ends 173, 193 and 213 are formed into an inner diameter sufficient to permit the inner ends 171, 191 and 211 to be received therein, respectively. More specifically, the outer ends 173, 193 and 213 each are so formed that a distance between an inner surface thereof and a center of the manhole repairing material is somewhat larger than a radius of the manhole repairing material, resulting in keeping any step or level difference from being formed inside each of the

cuts

11, 13 and 15 due to the overlap. The manhole repairing materials each are so formed that the overlap between the inner end and the outer end generally has a width of about 80 mm to 100 mm. However, when the inner surface 2 of the manhole structure is substantially is subject to corrosion to a degree sufficient to substantially increase an inner diameter of the manhole, the manhole repairing materials each are expanded, resulting in the width of the overlap being often reduced to a level as small as about 30 mm.

The

manhole repairing materials

1 and 3 have upper ends 23 and 25 constructed so as to be outwardly expanded, respectively, so that the upper ends 23 and 25 may be variably increased in an inner diameter so as to permit the lower end 27 of the manhole repairing material 3 and the short cylindrical section or lower end 7 of the material 9 to be received or fitted therein, respectively, to thereby keep any step or level difference from occurring on an inside of an overlap formed by superposition or laying therebetween. The upper ends 23 and 25 of the

manhole repairing materials

1 and 3 are also formed at a part thereof with outward expansions 29 and 31 for receiving the outer ends 193 and 213 of the

materials

3 and 9 therein, respectively.

The

manhole repairing materials

1, 3 and 9 each are provided on an outer peripheral surface thereof with a number of

projections

33 and 35, respectively. The

projections

33 and 35 each are formed by outwardly expanding a part of a peripheral wall of each of the

materials

1, 3 and 9, so that an inner peripheral surface of the material are formed with a number of recesses corresponding to the

projections

33 and 35. The projections 33 positioned at lower end portions 27 and 7 of the

materials

3 and 9 each are integrally formed with a hook 37 for fitted superposition or laying between the manhole repairing materials. The

projections

33 and 35 are formed so as to outwardly project by a distance of about 6 mm and 3 mm from the outer peripheral surface of the repairing materials, respectively. Also, the projections 33 arranged on each of the outer ends 173, 193 and 213 of the materials are preferably formed so as to project by about 3 mm. In Fig. 1, only the projections 33 on the outer end 193 are illustrated for the sake of brevity. A gap or distance between the inner surface 2 of the manhole and each of the

manhole repairing materials

1, 3 and 9 is effective to be between about 2 mm and about 10 mm. Thus, a distance or height of the projections 33 may be selectively determined within a range between 2 mm and 10 mm as desired. When smoothness of the inner surface of each of the manhole repairing materials is desired, the recess inside each of the projections may be charged with hardening resin. In Fig. 1,

reference numerals

39, 41 and 43 each designate suspension holes through which the manhole repairing material is suspended.

The

manhole repairing materials

1 and 3 each may be formed by subjecting fiber reinforced unsaturated polyester to molding by a hand lay up method using a die having a cylindrical outer surface and then subjecting it to rapping, followed by formation of the vertically extending cut 11 or 13. A portion of the material cut forms a distal end of the outwardly expanded portion of the material defined in a peripheral direction thereof. Formation of the manhole repairing material 9 is carried out using a die provided with a frust-conical outer surface of which an upper end is formed into a cylindrical shape and a lower end is formed into a cylindrical shape. Then, fiber reinforced unsaturated polyester is subject to molding by a hand lay up method using the die and then rapping, followed by formation of the vertically extending cut 15. A portion of the material cut likewise forms a distal end of the outwardly expanded portion of the material defined in a peripheral direction thereof. The dies used each have an outer surface substantially corresponding to the inner surface 2 of the manhole structure. The

cuts

11, 13 and 15 may be formed during the molding. The

manhole repairing materials

1, 3 and 9 each are made to be transparent.

Reference numeral 45 designates a pair of closing members made of a plastic material, each of which includes a rear plate 47 formed into a curved shape so as to correspond to a portion of the inner surface 2 of the manhole located at an opening 10 of a sewage pipe, a support bottom 49 formed so as to inwardly extend from a lower end of the rear plate 47 and a front plate 51 formed so as to upwardly extend from an inner end of the support bottom 49 and curved concentrically with the rear plate 47. The rear plate 47 and front plate 51 are arranged so as to be spaced from each other with an interval of about 5 mm being defined therebetween, resulting in providing a receiving groove 53 for receiving a lower end 52 of the manhole repairing material 1. As shown in Fig. 2, a bottom surface 12 of the manhole structure is generally formed so as to be downwardly inclined from both sides thereof toward a water channel 14 formed on the bottom surface 12 so as to pass through a center of the bottom surface 12, therefore, the lower end 52 of the manhole repairing material 1 is formed in such a manner that a bottom of each of left-hand and right-hand portions 48 and 50 thereof received in the receiving groove 53 of each of the closing members 45 is horizontal. Also, the lower end 52 of the manhole repairing material 1 is so formed that a bottom of each of portions 54 thereof between the left-hand portion 48 and the right-hand portion 50 ascends from both sides thereof toward a center thereof. This permits the portions 54 to substantially conform with an outer periphery of the bottom surface 12 of the manhole.

Now, arrangement of the closing members 45 and

manhole repairing materials

1, 3 and 9 in the manhole will be described hereinafter with reference to Figs. 3 to 9.

The closing members 45 are arranged in the manhole structure in such a manner as shown in Fig. 3. The inner surface 2 of the manhole is cleaned by blowing high-pressure water against the inner surface. When the inner surface 2 is highly polluted, a rotary brush may be used for the cleaning. Then, steps 16 are cut off and then the closing members 45 are arranged at the sewage pipe openings 10, resulting in closing or the openings 10 being completed. The closing members 45 are so arranged that the rear plates 47 each close an upper half of each of the sewage pipe openings 10 and the support bottoms 49 are positioned on both sides of the water channel 14 in a manner to interpose it therebetween. The rear plates 47 each are formed so as to tightly close the sewage pipe opening 10 and render a curvature thereof equal to that of the inner surface 2 of the manhole. Also, it is formed into a height larger by 50 mm to 100 mm than a radius of the sewage pipe opening 10 and a width larger by 100 mm to 200 mm than a diameter of the opening 10. The rear plate 47 thus formed is arranged on the inner surface 2 of the manhole with a sealing material being charged therebetween. A material adapted to be cured even in the presence of water such as, for example, water-cured concrete, quick-setting mortar or the like may be preferably used as the sealing material. When a plurality of such sealing materials are used, at least one of them is desirably a water-cured type. In the illustrated embodiment, as shown in Fig. 4, water-cured epoxy resin 55 is applied to both a portion of the inner surface 2 of the manhole around the sewage pipe openings 10 and a rear surface of the rear plates 47 and then the rear surface of the rear plates 47 is forced against the inner surface 2 of the manhole, resulting in the closing members 45 being arranged in the manhole structure. Also, water-cured epoxy resin 57 is applied to a periphery of each of the rear plates 47 to promote a sealing function. The rear plates 47 each may be formed into a semi-circular shape having a radius larger by 50 mm to 100 mm than that of the sewage pipe opening 10.

The manhole repairing material 1 is arranged in the manhole in such a manner as shown in Fig. 5. The manhole repairing material 1 is formed so as to exhibit a modulus in flexure of about 800 kg/mm² and tied by means of a cord, to thereby be reduced in diameter, resulting in being subject to overlapping as indicated at phantom lines in Fig. 1. Then, it is inserted through an entrance 18 of the manhole thereinto, followed by stacking or superposing operation as described hereinafter. Insertion of the manhole repairing material 1 is carried out by passing a suspension cord 59 through the suspension hole 39 of the material 1 and then downwardly moving the material 1 into the manhole as shown in Fig. 3. The manhole repairing material 1 thus inserted is then released from the overlapping, so that the lower end 52 of the material 1 is received in the receiving grooves 53 of the closing members 45 and carried on a periphery of the bottom surface 12 of the manhole.

After such arrangement of the manhole repairing material 1 in the manhole, an expansion equipment 61 constructed in such a manner as shown in Figs. 11 to 13 is inserted into the manhole repairing material 1 for expansion of the material 1, as shown in Fig. 3. The expansion equipment 61 includes a ring 63 made of spring steel and cut at a suitable position thereof so as to provide the ring 63 with both ends 65 and 80 opposite to each other in a peripheral direction thereof and an adjustment mechanism 66 mounted on one end 65 of the ring 63. The adjustment mechanism 66 includes a casing member 67, a revolving shaft 68 arranged in the casing member 67 in a manner to be rotatable and vertically extend, and a pinion 69 mounted on the revolving shaft 68 The casing member 67 is formed into a substantially sideways U-shape and includes an upper wall 71, a lower wall 72 and a connection wall 74 for connecting the upper and

lower walls

71 and 72 to each other therethrough. In the casing member 67 thus formed, the upper wail 71 and lower wall 72 are fixed at an open end thereof on upper and lower portions of the one end 65 of the ring 63, respectively, resulting in the connection wall 74 being inwardly positioned. The revolving shaft 68 is mounted on an upper end thereof with an adjustment section 76 of a large diameter. The adjustment section 76 is positioned on the upper wall 71 of the casing member 67 and formed with a hole of a hexagonal shape which is open at an upper end thereof. Then, a hexagonal rod-like tool 78 is fitted in the hexagonal hole for operation, to thereby rotate the revolving shaft 68, leading to rotation of the pinion 69.

Between the casing member 67 and the one end 65 of the ring 63 is inserted the other end 80 of the ring 63. The other end 80 is formed on an inner side thereof with a rack 82, which is engaged with the pinion 69. Thus, rotation of the pinion 69 by operation of the adjustment section 76 permits a degree of insertion of the other end 80 into the casing member 67 to be suitably adjusted as desired. This results in a width of overlapping between the one end 65 and the other end 80 being adjusted, to thereby permit a diameter of the ring 63 to be varied as desired. The connection wall 74 of the casing member 67 is formed with a through-hole which is provided therein with internal threads 84. Reference numeral 90 designates a stopper screw formed thereon with external threads 86 and provided at a rear end thereof with a ring element 88. The stopper screw 90 is threadedly inserted via the through-hole. Thus, the stopper screw 90 is threadedly forced into the casing member 67, to thereby be forcedly contacted with the pinion 69, leading to locking of the pinion 69, resulting in the ring 63 being kept expanded. Also, the ring 63 is mounted thereon with three suspension ring members 92. The ring members 92 each are formed with a passage, through which it is slidably fitted on the ring 63. The ring members 92, as shown in Fig. 13, each include a support section 98 formed into a substantially rectangular shape in section and formed with a through-hole provided with internal threads 96 and a screw 104 formed thereon with external threads 100 and provided at a rear end thereof with a ring element 102. The screw 104 is threadedly inserted via the through-hole of the support member 98 into the support member 98, to thereby be forcedly abutted against the ring 63, so that the suspension ring member 92 is positioned.

Insertion of the expansion equipment 61 in the manhole repairing material 1, as shown in Fig. 5, is carried out in such a manner that suspension cord 77 arranged so as to extend through a plurality of or three turnbuckles 75 mounted on a suspension wire 73 is connected to the ring elements 102 of the suspension ring members 92 of the expansion equipment 61 and then the equipment 61 is downwardly moved in the manhole repairing material 1. Connection of the cord 77 to the ring members 92 may be carried out by means of the ring elements 88 of the stopper screws 90. Then, the expansion equipment 61 is expanded while being suspended in the manhole repairing material 1, so that it outwardly forcedly press an inner surface of the manhole repairing material, to thereby enlarge the manhole repairing material 1, so that the

ribs

33 and 35 of the manhole repairing material 1 are pressed against the vertical surface section 6 of the inner surface 2 of the manhole, as shown in Figs. 1 and 6. When the expansion equipment 61 fails to be suspended while being kept horizontal, the turnbuckles 75 are operated to render the expansion equipment 61 horizontal. In the illustrated embodiment, a chain may be substituted for the rack 80 and correspondingly a sprocket may be mounted on the revolving shaft 68 so as to be engaged with the chain.

Then, the cut 11 of the manhole repairing material 1 is sealed with two-part cured silicone resin 79 and similarly a gap between the lower end of the repairing material 1 and the front plate 51 of each of the closing members 45 is sealed with two-part cured silicone resin 81. Also, a gap between the lower end of the manhole repairing material 1 and the bottom surface 12 of the manhole is sealedly closed with a sealing material, which is preferably curable even in the presence of water In the illustrated embodiment, as detailedly shown in Fig. 8, two-part cured silicone resin 83 is interposedly arranged between the lower end 52 of the manhole repairing material 1 and the bottom surface 12 of the manhole, followed by application of water-cured epoxy resin 85, and then quick-setting mortar is applied onto the water-cured epoxy resin 85. The two-part cured silicone resin 83 acts to close any possible gap between the lower end 52 of the manhole repairing material 1 and the bottom surface 12 of the manhole, therefore, it is not necessarily required to arrange the resin 83 at a portion at which the lower end 52 is contacted with the bottom surface 12 of the manhole. Then, a gap 89 between the inner surface of the manhole and an outer surface of the manhole repairing material 1 is charged with a small amount of waterstop curable resin 91, so that a waterstop structure sufficient to resist a liquid pressure of an Increased level may be provided below the manhole repairing material 1. The waterstop curable resin 91 may he charged so as to have a height of about 10 cm at an uppermost position on the bottom surface 12 of the manhole. The waterstop structure thus constructed of the sealing

materials

83, 85 and 87 and the waterstop curable resin 91 permits a cold setting impregnating material for lining which is charged in the subsequent step to be decreased in kinematic viscosity under any conditions. A decrease in kinematic viscosity of the impregnating material permits the material to be impregnated throughout any corroded and/or cracked portion of the inner wall 2 of the manhole, resulting in satisfactory reinforcing and waterstop function being exhibited. The waterstop curable resin 91 may comprise thermosetting resin. In the illustrated embodiment, cold setting acrylic resin of 100 cSt in kinematic viscosity at 25°C may be conveniently used as the resin 91.

The

manhole repairing materials

3 and 9 are inserted into the manhole in such a manner as shown in Fig. 9. The repairing

materials

3 and 9 each are likewise formed so as to exhibit a modulus in flexure of about 800 kg/mm² and reduced in diameter so as to be subject to overlapping. Then, the suspension cords 59 are connected to the suspension holes 41 and 43 as shown in Fig. 1 and the

materials

3 and 9 are inserted into the manhole while being suspended through the cords 59 as shown in Fig. 3. The manhole repairing material 3 thus inserted into the manhole is released from the overlapping, so that the lower end 27 of the material 3 is fitted in the upper end 23 of the repairing material 1. This results in the repairing material 3 being superposed or laid on the repairing material 1 while keeping the hooks 37 (Figs. 1 and 14) of the material 3 engaged with an outside of the upper end 23 of the material 1. Then, the expansion equipment 61 is inserted into the manhole repairing material 3 and then expanded, resulting in the ribs 33 and 35 (Fig. 1) being forcedly pressed against the vertical surface section 6 of the inner surface 2 of the manhole, followed by sealing of the cut 13 (Fig. 1) and a superposition region 95 between both

materials

1 and 3 with two-part cured silicone resin 97. Subsequently, the manhole repairing material 9 is inserted into the manhole structure, so that the short cylindrical section 7 is received or fitted in the upper end 25 of the manhole repairing material 5 while engaging the hocks 37 (Figs. 1 and 14) of the manhole repairing material 9 with an outside of the upper end 25 of the manhole repairing material 3, resulting in stacking or superposition between the

manhole repairing materials

3 and 9 being completed. Then, the expansion equipment 61 is operated to enlarge the manhole repairing material 9 to forcedly press the ribs 33 against the inclined surface section 8 of the inner surface 2 of the manhole and an upper portion of the vertical surface section 6 thereof, resulting in expansion of the material 9 being completed. The expansion equipment 61 for enlargement of the manhole repairing material 9 is preferably constructed so that an outer surface thereof is inclined in correspondence to the repairing material 9. Alternatively, the expansion equipment 61 may be so constructed that no inclined outer surface is provided on each of the cylindrical portion 4 and short cylindrical section 7 thereof, as shown in Fig. 10. Then, the cut 15 and a superposition region 99 between the

materials

3 and 9 are sealed with two-part cured silicone resin, resulting in arrangement of the

manhole repairing materials

1, 3 and 9 being completed. The operation for superposition by fitting is carried out so that the cuts 13 and 15 are conformed with the outer expansions 29 and 31 (Fig. 1), respectively. The upper ends 23 and 25 of the

manhole repairing materials

1, and 3, as shown in Fig. 14, may be provided on an inner surface thereof with an adhesive layer 105 covered with a released paper 103. When the superposition is started, the released paper 103 is removed from the adhesive layer 105 and the lower end 27 of the manhole repairing material 3 and the short cylindrical section 7 of the repairing material 89 are pressed against the adhesive layer 105, to thereby be adhered thereto, resulting in the operation for superposition being readily and conveniently accomplished. Also, the outer ends 173, 193 and 213 of the vertically extending

cuts

11, 13 and 15 each may likewise have an adhesive layer 109 provided thereon while being covered with a released paper 107, to thereby ensure adhesion between the outer ends 173, 193 and 213 and the inner ends 171, 191 and 211 during the expansion, so that the

manhole repairing materials

1, 3 and 9 may be kept uniformly expanded. Further, in order to effectively prevent leakage the cold setting impregnating material to the inside,

leakage preventing sponges

111 and 113 are preferably arranged on upper and outer sides of the cuts, respectively, as shown in Figs. 14 and 15. Outer expansion of the upper ends 23 and 25 and outer ends 173, 193 and 213 may be set to be about 2 mm. When the

adhesive layers

105 and 109 are arranged, the expansion may be set to be in the order of 3 mm. Thus, the projections 35 and the projections 33 on the outer ends 173, 193 and 213 each may he formed into a height of about 4 mm when the

adhesive layers

105 and 109 are not arranged.

After arrangement of the

manhole repairing materials

1, 3 and 9 is thus completed, a cold setting impregnating material 115 for lining is downwardly charged throughout the gap 89 between the repairing

materials

1, 3 and 9 and the inner surface 2 of the manhole, to thereby carry out lining. For this purpose, a liquid rubber material such as liquid urethane resin, polybutadiene or the like may be used as the impregnating material 115. However, cold setting epoxy resin, acrylic resin or unsaturated polyester resin which is inexpensive and exhibits good adhesion properties may be suitably used for this purpose Alternatively, thermosetting resin may be used as required. Also, water glass or cement milk may he selectively used. In the illustrated embodiment, cold setting epoxy resin of 300 cSt in kinematic viscosity at 25°C is used to this end. The cold setting impregnating resin 115 for lining preferably has kinematic viscosity of 3000 cSt or less at 25°C. Particularly preferably, the kinematic viscosity at 25°C is between 100 cSt and 500 cSt.

A period of time required for curing conventional cold setting resin is generally in the order of 1 to 6 hours. Therefore, it is preferable that charging of the cold setting impregnating material 115 after setting or arrangement of the

manhole repairing materials

1, 3 and 9 in the manhole is carried out at one time in order to reduce a period of time required for the repairing. Alternatively, the charging may be carried out in several times, wherein each charging takes place after the cold setting impregnating material 115 charged by the preceding charging operation is cured or semi-cured. Also, the charging may take place every time when setting of each of the

manhole repairing materials

1, 3 and 9 is carried out.

Alter the cold setting impregnating material 115 is cured, the expansion equipments are removed from the repairing materials, followed by formation of holes 117 at the sewage pipe openings 10 and arrangement of new steps (not shown). Then, the holes 117 are covered on a cut surface thereof with curable resin such as epoxy resin or the like, resulting in an appearance of the manhole being finished. Thus, the repairing operation is completed. The cold setting impregnating material 115, as shown in Fig. 18, is fully impregnated into any corroded and/or cracked portion of the inner surface 2 of the manhole and cured. When the lining layer is formed of only cold setting impregnating material 115 while keeping the

manhole repairing materials

1, 3 and 9 removed from the manhole, a released material is applied to the outer surface of the repairing materials. However, when the repairing materials are made of resin exhibiting satisfactory release characteristics such as polypropylene, polyethylene, fluororesin or the like, application of a released material thereto is eliminated.

Referring now to Fig. 19, another embodiment of a manhole surface repairing method according to the present invention is illustrated. In the illustrated embodiment, an elongated repairing material 119 of a cylindrical shape and a frust-conical repairing material 121 is substituted for the

manhole repairing materials

1, 3 and 9 in the embodiment described above. The cylindrical repairing material 119 and frust-conical repairing material 121 are formed with vertically extending

cuts

123 and 125, respectively. Also, the repairing

materials

119 and 121 are formed on an outer surface thereof with projections 127 for formation of a gap. The projections 127 are arranged so as to vertically extend from an upper end of each of the repairing

materials

119 and 121 to a lower end thereof and be spaced from each other at equal intervals in a circumferential direction of the repairing material. The frust-conical repairing material 121 may be provided on an upper end thereof with a cylindrical portion. The repairing material 119 is so constructed that a lower end 129 thereof has a left-hand portion 131 and a right-hand portion (not shown) defined on a horizontal plane. Also, the lower end 129 has intermediate portions 133 defined between the left-hand portion 131 and the right-hand portion, each of which is farmed so as to be gradually raised from both sides thereof toward a center thereof. The intermediate portions 133 are formed so as to be conformed with a periphery of a bottom surface 12 of the manhole.

The remaining part of the illustrated embodiment may be constructed in substantially the same manner as the embodiment described above.

While preferred embodiments of the invention have been described with a certain degree of particularity with reference to the drawings, obvious modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

In accordance with another aspect of the present invention, an expansion equipment is provided which is adapted to outwardly force an inner surface of a repairing material structure to expand the repairing material structure. The expansion equipment includes a ring formed with one cut, resulting in being provided at the cut with one end and the other end which overlap each other in a circumferential direction of the ring and an adjustment mechanism mounted on the one end of the ring. The adjustment mechanism includes a casing member, a revolving shaft arranged in the casing member so as to be rotatable and extend through the casing member, and a pinion securely mounted on the revolving shaft and arranged in the casing member. The other end of the ring is inserted between the casing member and the one end of the ring and provided on an inside thereof with a rack adapted to be engaged with the pinion.

Claims

A method for repairing an inner surface (2) of a manhole by lining, comprising the steps of:

arranging a thin-wall repairing material structure (1, 3, 9) made of a plastic material in the manhole so as to cover the inner surface of the manhole with a gap being defined between the repairing material structure and the inner surface of the manhole; and

charging a liquid cold setting impregnating material (115) for lining in said gap and curing it.
A method as defined in claim 1, characterized in that said repairing material structure is formed into a cylindrical shape and provided with one vertically extending cut; and

said method further comprises the steps of:

inserting said repairing material structure into the manhole while reducing a diameter of said repairing material structure so as to subject it to overlapping at said cut; and

releasing said repairing material structure from the overlapping to expand said repairing material structure, to thereby position it in the manhole.
A method as defined in claim 1, characterized in that said repairing material structure includes cylindrical repairing bodies (1, 3) and a cylindrical repairing structure (9) of a frust-conical shape carried on said cylindrical repairing structure.
A method for repairing an inner surface (2) of a manhole by lining, comprising the steps of:

providing a plurality of thin-wall cylindrical repairing materials (1, 3) made of a plastic material so as to cover a vertical surface section (6) of the inner surface of the manhole and each provided with one vertically extending cut and a thin-wall cylindrical repairing material (9) made of a plastic material so as to cover an inclined surface section (8) of the inner surface of the manhole as required and provided with one vertically extending cut;

inserting said repairing materials (1, 3, 9) into the manhole while reducing a diameter of said repairing materials to subject each of said repairing materials to overlapping and laying said repairing materials on each other by fitting;

expanding said repairing materials during or after the laying, to thereby cover the inner surface of the manhole with said repairing materials with a gap being defined between the repairing materials and the inner surface of the manhole; and

charging a liquid cold setting impregnating material (115) in said gap between the inner surface of the manhole and said repairing materials and curing the impregnating material, to thereby carry cut lining on the inner surface of the manhole.
A method as defined in claim 1 or 4, characterized in that said repairing material structure is previously formed at a lower end (52) thereof into a shape corresponding to undulation of a bottom surface (12) of the manhole.
A method as defined in claim 1 or 4, charatcerized in that said repairing material structure is inserted into the manhole after closing members (45) for closing sewage pipe openings (10) are arranged at the sewage pipe openings, so that liquid leakage to a water channel is prevented.
A method as defined in claim 6, characterized in that said repairing material structure is supported at a lower end )52) thereof on said closing members.
A method as defined in claim 7, characterized in that said closing members each are formed with a receiving groove (53); and

said repairing material structure is supported on said closing members while being received at the loner end thereof in said receiving groove.
A method as defined in claim 4, characterized in that one of a lower end of upper one (3) of each adjacent two of said repairing materials and an upper end of lower one (1) thereof is formed into a diameter larger than the other; and

the step of laying said repairing materials on each other is carried out by fitting between said lower end and said upper end.
A method as defined in claim 2 or 4, characterized in that said repairing material structure has two ends defined at said cut so as to be opposite to each other in a circumferential direction thereof;

said two ends are formed into inner diameters different from each other; and

the step of expanding said repairing material structure is carried out in such a manner that said two ends overlap each other.
A manhole repairing material structure used in a method for repairing an inner surface of a manhole by lining, comprising:

a plurality of thin-wall cylindrical bodies (1, 3) made of a plastic material and adapted to be laid on each other;

said cylindrical bodies each being provided with one vertically-extending cut, resulting in being expandable,

said cylindrical bodies being formed on an inner or outer side thereof into a large diameter.
A manhole repairing material structure used in a method for repairing an inner surface of a manhole by lining, comprising:

a thin-wall cylindrical body (9) including a frust-conical section (5) and a short cylindrical section (7) provided on a lower end of said frust-conical section,

said cylindrical body being provided with one vertically extending cut.
A manhole repairing material structure as defined in claim 12, characterized in that said cut of said manhole repairing material (1, 3, 9) has both ends defined so as to be opposite to each other in a circumferential direction of said cylindrical body; and

one of said both ends has an inner diameter larger than that of the other end.
A manhole repairing material structure as defined in claim 11 or 12, characterized in that said manhole repairing material (1, 3, 9) is integrally provided thereon with a plurality of vertically extending projections (33, 35) for gap formation in a manner to be distributed in a circumferential direction thereof or a plurality of small projections for gap formation.
A manhole repairing material structure as defined in claim 11 or 12, characterized in that said manhole repairing material (1, 3, 9) is transparent or semi-transparent.
A closing member for preventing leakage of a liquid impregnating material charged in a gap between a cylindrical repairing material structure and an inner surface of a manhole, comprising:

a rear plate (47) formed so as to be curved in correspondence to a portion of the inner surface of the manhole which is positioned at a sewage pipe opening (10); and

a support bottom (49) which is formed so as to inwardly extend from said rear plate and on which the repairing material structure is supported at a lower end thereof.
A closing member as defined in claim 16. characterized in that said closing member further comprises a front plate (51) formed inside said support bottom so as to define a narrow receiving groove (53) between said front plate and said rear plate.
An expansion equipment for outwardly forcing an inner surface of a repairing material structure to expand the repairing material structure, comprising:

a ring (63) formed with one cut, resulting in being provided at said cut with both ends which overlap each other: and

an adjustment mechanism (66) for adjusting a width of overlap between said both ends to fix said both ends.