JOINT SEALING MEMBER

Abstract: A joint sealing member (l7) such as may be used in civil engineering works for providing a watertight seal be­ tween joint members is disclosed. In one embodiment, the sealing member takes the form of a belt-like base plate made of a water expansible material having one or more longitudinally extending rib-like ridge portions formed on one side thereof.

Description: The present invention relates to band-like joint sealing members for providing a water-tight seal between members in a civil engineering construction or the like. Sealing elements for such purposes are already known. In FR-A 2 293 574 there are disclosed sealing members made of elastic material with a plurality of ridges on one face or on opposite faces. In JP-A 58 187 655 there is disclosed a sealing member made of a watertight substance containing a resin which swells and gels by absorbing water. The present invention provides an improved sealing element over the prior known art. For example, as shown in Figures 1, 2A and 3, plural unit segments 1 are used as work materials in constructing a shield tunnel excavated underground. These unit segments 1 are closely joined in the direction a along the peripheral wall and in the longitudinal direction b of the gallery. At the four sides of a plate portion of each of segments 1, there are provided front and rear flanges 2 and 3 extending in the circumferential direction a around the peripheral walls, and upper and lower flanges 4 and 5 extending in the longitudinal direction b . When these segments are joined, the adjacent flanges 2 and 3, and the adjacent flanges 4 and 5, are respectively joined and clamped by means of joint bolts 6. In order to prevent water seeping out of the earth around the gallery from leaking into the gallery, it is necessary to provide a water-tight seal at the respective junctions of the joined flanges. To this end, a band-like joint sealing member 8 is secured by bonding onto one side of the flange surfaces facing gaps 7 between adjacent flange surfaces. For the illustrated conventional sealing member 8, for example, a well-known water expansible material such as a material obtained by mixing, synthesizing and vulcanizing high hygroscopic resin and synthetic rubber is used. The sealing member 8 is formed into a single layer using the above-mentioned material. The sealing member 8 expands due to infiltration of water W into the joint so as to watertightly seal the gap 7. In order to completely perform so-called initial water stopping processing before the sealing member expands due to water absorption by using such a conventional sealing member 8, it is necessary to make the sealing member 8 thicker, in which case not only is the material cost high, but also there occurs frequently a problem of the sealing member 8 becoming more easily dislodged from the junction of the segment 1 in transport or the like. Figure 2B depicts another prior art arrangement. In the middle portion in the direction of width of each of the outer surfaces of the flanges 2 and 4 of each of the segments a belt-like fitting groove (for example, a groove 4a in the flange 4) is formed, and a joint member 8 is fixed in each of the fitting grooves. The surface of the joint member 8 projects from the outer surface of each of the flanges 2 and 4. The flanges 2 and 3 of the respective segments 1A and 1C are fixedly clamped together by three connecting bolts 6, and the flanges 4 and 5 of the respective segments 1A and 1B are fixedly clamped by two connecting bolts 6 such that the joint member 8 is compressed by a thickness t and the outer surface of the joint member 8 is urged against the outer surface of the flange 5 by elastic force, thereby effecting water stopping processing at the joint junction. In this arrangement, the joint member 8 must be made thicker so as to sufficiently include the thickness t therein so that the joint member 8 largely projects from the flange 4. Accordingly, not only is a large amount of effort required for screwing on the nuts 6a, but also the projecting edge of the joint member 8 is apt to be caught thereby, causing the joint member 8 to slip out of the fitting groove 4a. JP-A-37184/82 describes a water stopping piece which is made from water expandable rubber. The piece is used to stop water penetrating through the joint between two pipes. The piece is located in a groove at the end of the inner pipe. The piece expands in water in order to provide a seal but no initial seal is provided. JP-A-58-59898 describes a water stopping structure which is located in at least one groove between two mating surfaces. The structure is made of water expandable rubber and the effective seal is developed only after the water has caused expansion of the structure. The present invention has been attained to solve the difficulties mentioned above. A specific object of the present invention is to provide a joint sealing member constituted by a water expansible material in which effective expansion in the direction of thickness can be obtained, stable bonding of the bottom surface of the sealing member can be obtained, and effective initial water stopping processing can be accomplished without increasing the thickness of the sealing member. The object of the invention is solved by a water-tight seal between frame members (1) in a civil engineering construction comprising a band-like joint sealing member (17) having a band-like base (17a) made of a water-expansible material with one or more ridge portions (17b) formed longitudinally and integrally of the same material on one side of said base (17a), wherein the cross-section of the sealing member as viewed transversely to the running length of the ridge portions (17b) comprises: (a) a band-like base having parallel upper and lower straight lines defining the upper and lower faces of the band-like base (17a); (b) said one or more ridges (17b) occupying only part of the extent of said upper line; and in a spaced apart manner along said upper line when there is more than one ridge on said upper line; (c) said sealing member (17) being disposed in a groove (16a) formed in one of two adjacent and joined frame members (1), the thickness of the band-like base (17a) being substantially equal to the depth of said groove (16a); and (d) the height of said band-like sealing member (17) being greater than the distance between the base of the groove (16a) formed in one of said two adjacent and joined frame members (1) and the opposing surface of the other of said two adjacent and joined frame members (1). For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a perspective diagram of a portion of a sealed construction; Figures 2A and 2B are cross-sectional views taken along a line II-II in Figure 1; Figure 3 is a perspective view, partially cut away, of a sealing member employed in the arrangement of Figure 2A; Figure 4 is a cross-sectional view, similar to Figure 2B, but illustrating sealing members according to a first embodiment of the invention; Figure 5 is an enlarged cross-sectional view of a portion of Figure 4; Figure 6 is a perspective view of a sealing member used in the embodiment of Figures 4 and 5; Figure 7 shows the sealing member of Figure 6 after it has been swollen by impregnation with water; Figure 8 shows configurations of other embodiments of sealing members of the invention. Referring to the drawings, the present invention will be described hereunder. As to the terms used in the following description, with respect to directions, the terms "upper and lower" and "thickness" are used with respect to the vertical direction in the drawings, and the terms "left and right", "width", and "transverse" are used in conjunction with the horizontal direction in the drawings. Figure 4 shows a section of a joint junction portion where a wide joint member 17 (one embodiment) and a similarly shaped narrow joint member 18 (another embodiment) are fixed in two rows between a flange 15 of a segment 1D and a flange 16 of a segment 1E. The joint members 17 and 18 are respectively adhered to fitting grooves 16a and 16b of the flange 16. Referring to Figures 5 to 7, the joint member 17 will be described in detail (the same applies to the joint member 18). The joint member 17 is made of a material obtained by mixing, synthesizing and vulcanizing a water expansible material such as high-grade water resin and synthetic rubber. As the synthetic rubber, 1,3 diene group rubber containing a crystal domain (or glassy domain) of 5 to 10% at a normal temperature is used. The joint member 17 has two rows of rib-like ridge portions 17b each having a substantially semi-circular cross-section extending upwardly from one surface of a strip-like elongated base plate portion 17a. The thickness of the base plate 17a of the joint member 17 is substantially the same as the depth of the fitting groove 16a so that the surface of the base plate 17a is substantially even with the surface of the flange 16. Each of the ridge portions 17b is shaped to have a crest which is high enough to sufficiently project to fill the width t so that, in the state in which the nut 6a is screwed onto the connecting bolt 6 as shown in Figures 4 and 5, the crest portion of each ridge portion 17b is compressed by the thickness t and caused to closely contact with the surface of the flange 15 by its own elastic force. With the joint member 17 according to this embodiment (the same applies to the joint member 18) arranged in the manner as described above, not only is there an advantage of saving material because of the smaller thickness of the base plate 17a, but also, since the base plate 17a becomes substantially even with the face of the flange 16, there is no risk that the joint member will be pulled out of the fitting groove 16a in the joint connecting operation. Moreover, since the crest portion of the ridge portion 17b is compressed when the fixing nut 6a is screwed on, the tightening operation can be easily performed. The joint member 17 of this embodiment provides sufficient watertightness due to close contact by the ridge portions 17b even at the initial stage, and after absorbing water, as shown in Figure 7, the entire joint member 17 conforms to the flange 15 due to the force of expansion so that watertightness is always maintained. Although it is preferable to use the joint member according to this embodiment of the present invention received in a fitting groove, the advantageous effects of the invention can be attained even in the case where the joint member is attached to a junction having no fitting groove. In addition to the case of water stopping processing at the joint junction of tunnel segments, the joint member according to the present invention can be widely used with the same effects in water stopping processing in joints of secondary concrete products such as culvert boxes, manholes, or the like, in joints of secondary steel products, colgate pipes, or the like. In this case, the shape of the cross-section of the joint member is properly established in accordance with the conditions at hand. Possible shapes for the joint member are shown in Figure 8, chosen taking the following design factors into consideration. (a) Base Plate: As the shape of the base plate, a rectangle, trapezoid, oblique trapezoid, or the like, is preferable. As the thickness is increased, the watertightness is improved, while the workability for installation is lowered so as to cause, for example, a reduction in the strength of reinforcement. On the contrary, if the base plate is made too thin, the opposite result is caused. (b) Number of ridge portions: Two rows are preferable. In the case of one row, the member is superior in compressibility and retention, but inferior in watertightness. The opposite result is caused in the case of three ridge portions. (c) Shape of ridge portions: A shape such as an arch, triangle, rectangle, oblique trapezoid, or the like, may be employed. It need not be isogonal or symmetrical. It is proper to select the height of the ridge portion in a range of 5% to 300% (20-150% is more preferable) of the thickness of the base plate of the joint member. Although the width of the ridge portion is not specifically limited, it is preferable to select it to be 10-40% of the width of the base plate of the joint member. It is preferable to select the sectional area of the ridge portion to be 1-200% of the sectional area of the base plate (5-100% is more preferable). If the ridge portion is too small, it is inferior in compressibility as well as in retention, and if it is too large, on the contrary, the watertightness is lowered. As described above, a joint member for civil engineering works according to the present invention is formed such that longitudinally extending rib-like ridge portions are formed integrally on one surface of a belt-like base plate made of a water expansible material so that it is possible not only to reduce the cost of the joint member due to the reduction in thickness of the joint member, but also to improve its ease of installation.

Claims: A water-tight seal between frame members (1) in a civil engineering construction comprising a band-like joint sealing member (17) having a band-like base (17a) made of a water-expansible material with one or more ridge portions (17b) formed longitudinally and integrally of the same material on one side of said base (17a), wherein the cross-section of the sealing member as viewed transversely to the running length of the ridge portions (17b) comprises: (a) a band-like base having parallel upper and lower straight lines defining the upper and lower faces of the band-like base (17a); (b) said one or more ridges (17b) occupying only part of the extent of said upper line; and in a spaced apart manner along said upper line when there is more than one ridge on said upper line; (c) said sealing member (17) being disposed in a groove (16a) formed in one of two adjacent and joined frame members (1), the thickness of the band-like base (17a) being substantially equal to the depth of said groove (16a); and (d) the height of said band-like sealing member (17) being greater than the distance between the base of the groove (16a) formed in one of said two adjacent and joined frame members (1) and the opposing surface of the other of said two adjacent and joined frame members (1). A seal as claimed in claim 1, wherein a height of said ridge portion or portions is selected in a range of 20-150% of the thickness of said base, a width of said ridge portion or portions is selected to be 10-40% of the width of said base and a sectional area of said ridge portion or portions is selected to be 1-200% of the sectional area of said base.

Inventors: KAMEDA, TAKAHIDE C/O C.I. KASEI CO. LTD., SHINJO, HIROSHI C/O C.I. KASEI CO. LTD., TAKASAKI, KAZUHIRO C/O C.I. KASEI CO. LTD., TERAUCHI, MICHIYOSHI C/O C.I. KASEI CO. LTD.
Applicants: C.I. KASEI CO., LTD
Application year: 1984
Main classification: E21D11
IPC codes: E21D11, E04B1