JP2011127273A - Sheet pile with water drainage function and water catchment function and wall body structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel sheet pile with a water drainage function and a water catchment function capable of achieving excellent driving and construction performance when constructing the sheet pile and a water drainage member simultaneously, setting the optimum arrangement of the water drainage member, and reducing cost of materials and cost of construction and to provide a wall body structure constituted by installing the steel sheet piles continuously. <P>SOLUTION: In this sheet pile with the water drainage function including the water drainage members 3 along the longitudinal direction of the sheet pile 1 having effective width of 500 mm or more, an opening rate of the water drainage member 3 is 5% or more, more preferably 10% or more, and width of the water drainage member 3 is 170 mm or more. When constructing a sheet pile wall B by installing the sheet piles with the water drainage function continuously, a ratio of area of the water drainage member 3 to projected area of sheet pile wall body is set to be 15% or more, more preferably 20% or more. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a sheet pile with a drainage function used for a wall body or a revetment constructed on the ground where liquefaction is a concern during an earthquake, and a sheet pile wall formed by continuously installing the sheet pile.

  Various methods have been developed in the past when constructing a structure on the ground where liquefaction may occur during an earthquake, such as a soft sand layer ground, or when taking measures against liquefaction on an existing structure.

  For example, a compaction method (such as a sand compaction pile method) that increases the strength (density) of the ground so that the ground does not liquefy, a ground improvement method using chemical injection, and the like are widely applied.

  However, in this method, it is necessary to take measures for the surrounding ground over a considerably wide area, so it is necessary to secure the site, and it is important to improve the structure foundation ground board in order to exhibit the effect reliably. When considering application to an existing structure, it is necessary to remove the structure once and improve the ground, and then install the structure again, or improve the structure base ground from the ground around the structure.

  However, it is conceivable that there are restrictions on the application such as construction space restrictions and low noise / low vibration construction. Furthermore, depending on the countermeasure construction method and the range of ground improvement, it may be irrational because a large construction period and cost are required.

  On the other hand, methods such as the drain method that reduce excessive pore water pressure generated during an earthquake to suppress liquefaction, methods that structurally suppress ground deformation using steel, etc., and combinations of these technical elements Therefore, construction methods that enable more rational and effective measures have been developed. For example, sheet piles with piles, steel sheet piles with drainage function, steel pipe sheet piles, steel pipe piles, and H-shaped steels with a drainage function attached to steel materials such as sheet piles, piles, and H-shaped steels. Is mentioned.

  This construction method is often installed mainly on both sides of a linear structure such as a waterway, a common ditch, and embankment, or is installed so as to surround various facilities including buildings.

  By constructing walls around these structures, the deformation of the liquefied ground is suppressed by taking advantage of the strength and rigidity of the steel, and the effect of the drainage member installed on or near the steel It can be expected that excessive pore water pressure generated during an earthquake is reduced and liquefaction is suppressed, and harmful deformation and damage occurring in the structure are suppressed.

  If the generation of excess pore water pressure near the sheet pile is suppressed, the ground strength in the vicinity of the sheet pile can be maintained, and the reaction force from the ground that resists deformation of the steel material itself can be expected sufficiently, and the load from the ground acting on the steel material can be expected. Therefore, the necessary cross section of the steel material can be reduced, and cost rationalization can be expected.

  In addition, steel materials such as steel sheet piles and steel pipe sheet piles with drainage and water collection functions can be applied to the construction of retaining wall structures such as revetments and road retaining walls. By effectively draining the water on the back, it is expected to reduce the hydrostatic pressure and suppress the deformation of the retaining wall structure. Thereby, the cross section of the steel material applied to the retaining wall structure is reduced, and the material cost can be reduced, which is rational.

  As a conventional technique, for example, Patent Document 1 discloses that a case where a casing is driven into a sandy ground using vibration while the sandy ground is compacted, a pressure resistance against a predetermined pressure of the ground, and a peripheral wall A drain pipe with a water permeable filter covered with a pipe having a hole for water permeability inserted in the casing, and pulling the casing from the sandy ground to leave the drain pipe on the sandy ground And a method for countermeasures against liquefaction of sandy ground, characterized in that the excess pore water pressure in the sandy ground is reduced by using this drain pipe.

  In Patent Document 2, a cylindrical casing member having water absorption or water permeability is fixed to a sheet pile, and a cylindrical casing that covers the entire drain member is attached to the sheet pile. Attach the sheet pile and casing to the ground at the same time in a detachable manner, pour water into the casing to close the upper end opening, and leave the sheet pile and drain member in the ground. A ground liquefaction suppression method characterized by pulling up the casing in a state is described.

  Moreover, in patent document 3 by the applicant of this application, in the predetermined area along the longitudinal direction of a sheet pile main body, it is for drainage provided with the filter for preventing intrusion of many earth openings and ground earth and sand from this opening part. A steel sheet pile with a drainage function is described in which one or a plurality of members are provided on at least one side of the sheet pile main body.

  In addition, in Non-Patent Document 1, the wall body, which has been a problem in the past, is not hindered by the smooth flow of groundwater by forming an opening hole for water flow in the sheet pile wall body at normal times. It is described that the problem of well drainage and water level drop in the back can be solved. In this document, if an opening hole of about 1% per wall projection area is provided, about 90% of the water permeability in the normal state It is evaluated in the analysis that can be secured.

Japanese Patent Publication No. 06-011990 Japanese Patent Laid-Open No. 11-158862 Japanese Patent Laid-Open No. 02-225712

“Permeable steel sheet pile construction method with excellent preservation of groundwater environment”, Steel Pipe Pile Association Steel Sheet Pile Technical Committee brochure, Steel Pipe Pile Association

  Although the invention described in Patent Document 1 can be expected to dissipate excess pore water pressure around the drain pipe during an earthquake, the drain pipe cannot be expected to have rigidity, and the drain pipe deforms greatly due to ground deformation and flow. This may impair the function of the drain pipe and may damage the target structure to which measures are taken.

  In order to solve this problem, it is possible to use a wall structure such as a steel sheet pile that can be expected to have high rigidity. However, in that case, it is necessary to construct the drain pipe and the steel sheet pile separately, which requires construction time. This increases the construction cost and is not reasonable.

  In addition, although the invention described in Patent Document 2 can simultaneously construct the casing and the sheet pile covering the drain material and the entire member, it is necessary to pull out the casing tube, and the construction time becomes longer. Cost increases.

In addition, in order to obtain a sufficient drainage effect, it is necessary to increase the volume of the drain material,
The protective member which covers the end surface protective member and drain material which installs it also becomes large. This increases the resistance from the ground during construction and increases the construction cost due to the longer placement time. In addition, there is a concern that it may become difficult to place if the earth and sand in the gap between the sheet pile and the casing tube are clogged and compacted.

  Furthermore, the end face protection member is detachable in order to pull out the casing tube after placing, but if earth or sand flows into the casing tube during placement, the casing is removed when the casing tube is pulled out. There is a concern that the drain material installed in the pipe will be damaged and a sufficient drainage function will not be ensured.

  Moreover, since the invention described in Patent Document 3 is designed to place a steel sheet pile with a drainage member attached thereto, construction time can be shortened, and ground resistance during construction is also described in Patent Document 2. Although it is possible to reduce the size of the construction method, it is effective and economical, but the optimal arrangement of the drainage members is not clear.

  In general, when the drainage member is attached to the sheet pile, the interval at which the drainage member is installed in the wall direction tends to depend on the shape and size of the sheet pile and the material and size, structure, and strength of the drainage member. Therefore, it is necessary to set the installation interval and length of the drainage member in consideration of economy.

  If the drainage members are installed fairly densely, the decrease in drainage due to the installation interval can be reduced, but the drainage member cost increases correspondingly and the economy is inferior. On the other hand, if drainage members are installed fairly sparsely, drainage member costs are reduced and the cost is excellent, but the installation interval is increased accordingly, and there is a concern that drainage performance will be reduced.

  Further, if the length of the drainage member is longer than necessary, the resistance received from the ground at the time of construction increases, the construction time becomes longer, the construction cost increases, and the member cost increases. On the other hand, if it is shorter than necessary, there is a concern that the amount of drainage required at the time of the earthquake cannot be drained, and the countermeasure effect is reduced.

  In addition, in Non-Patent Document 1, analysis is evaluated that it is possible to secure about 90% of the amount of water permeation in a normal state by providing about 1% of the aperture hole for water passage in the sheet pile wall body per wall projection area. However, this is in a steady state.

  The sheet pile with drainage function that expects the dissipation of excess pore water pressure generated during an earthquake handles dynamic problems during an earthquake, so it cannot be said that sufficient drainage is possible with an aperture ratio comparable to the steady state. It is necessary to set the required aperture ratio by drainage analysis and experiments that take into account ground conditions such as water permeability, ground compression coefficient, etc.

  As described above, in the conventional technology, it is possible to construct a sheet pile and a drain material at the same time, and it is excellent in placing characteristics, the material cost and the construction cost are low, and the drainage member is optimally arranged with respect to the sheet pile. It is not a reasonable and economical construction method.

  Therefore, the present invention is intended to solve such a problem, and is excellent in placing property when the sheet pile and the drainage member are constructed at the same time, sets the optimal arrangement of the drainage member, and material cost and construction cost. It aims at providing the wall structure which installed the steel sheet pile which gave the drainage function and water collection function which can suppress water, and this steel sheet pile continuously.

The sheet pile with drainage function according to claim 1 is a sheet pile with drainage function in which a drainage member is provided along the longitudinal direction of the sheet pile having an effective width of 500 mm or more, and the member opening ratio of the drainage member is 5% or more, and drainage The width of the member is 170 mm or more.

  According to a second aspect of the present invention, in the sheet pile with a drainage function according to the first aspect, a member opening ratio of the drainage member is 10% or more.

  The sheet pile with drainage function according to claim 3 has a ratio of the drainage member to the sheet pile wall projection area of 15 when the sheet pile with drainage function according to claim 1 or 2 is continuously installed to construct the sheet pile wall. % Or more.

  According to a fourth aspect of the present invention, in the sheet pile with a drainage function according to the third aspect, a ratio of the drainage member to a sheet pile wall projection area is 20% or more.

  Claim 5 is characterized in that when the sheet pile with drainage function according to claims 1 to 4 is continuously installed to construct a sheet pile wall, the wall direction length in which the drainage member is not installed is 1.0 m or less. It is what.

Claim 6 is a sheet pile with a drainage function according to claims 1 to 5, wherein the drainage member has a sectional area of 20 cm ² or more, and the drainage member has a thickness in the direction perpendicular to the axis of 10 mm or more. It is what.

  The sheet pile with a drainage function according to claim 7 has a wall projection area ratio of 0.5% or more on the sheet pile main body when the sheet pile with drainage function according to claims 1 to 6 is continuously installed to construct a sheet pile wall. An opening hole for ensuring a smooth flow of groundwater is provided, and a sheet pile with a drainage function is provided with a water permeability function.

  According to an eighth aspect of the present invention, in the sheet pile with drainage function according to the first to seventh aspects, a position where the drainage member is installed is a sheet pile web portion.

  Claim 9 is characterized in that in the sheet pile with drainage function according to claims 1 to 8, the drainage member is installed only above the lower end of the layer where liquefaction is a concern during an earthquake. .

  Claim 10 is a sheet pile with a drainage function according to any one of claims 1 to 9, wherein the drainage member is a mat-like resin net-like structure, and water and sand are secured on the resin net-like structure while ensuring water permeability. A filter for preventing intrusion is provided.

  An eleventh aspect of the present invention is the sheet pile with a drainage function according to the tenth aspect, wherein a protective plate having a water permeability hole larger than the mesh of the filter is further provided on the filter for preventing damage to the filter. Is.

  Claim 12 is a sheet pile with a drainage function according to claims 1 to 11, wherein the drainage member and the sheet pile are discretely fixed along the distal end portion of the drainage member and the sheet pile longitudinal direction. It is.

  The sheet pile wall structure with a drainage function according to claim 13 is constructed by continuously installing and constructing a sheet pile with a drainage function according to claims 1 to 12.

  A sheet pile wall structure with a drainage function according to claim 14 is used as a sheet pile cutoff for a structure installed on a liquefiable ground, and at least the drainage is disposed inside the sheet pile cutoff where the structure exists. The member is positioned.

  The present invention is a sheet pile with a drainage function in which a drainage member is provided along the longitudinal direction of a sheet pile having an effective width of 500 mm or more, the member opening ratio of the drainage member is 5% or more, and the width of the drainage member is 170 mm or more. The material cost is reduced by reducing the steel weight per unit length by making the steel sheet pile larger, and the construction cost is reduced by reducing the construction cost by reducing the number of placements per construction extension. As will be described in detail in the section of the embodiment for carrying out the invention, it is possible to construct a wall body having a rational and strong drainage function.

As an example of the cross-sectional shape of a steel sheet pile, (a) is a conventional U-type steel sheet pile with an effective width of 400 mm, (b) is a U-type steel sheet pile with an effective width of 600 mm, and (c) is a state in which a hat-type steel sheet pile with an effective width of 900 mm is connected. It is sectional drawing shown. The example of the wall body which has the drainage function which combined H-shaped steel with the steel sheet pile is shown, (a) is sectional drawing, (b) is a perspective view. The example of the wall body which has the drainage function which combined H-shaped steel with the steel pipe and the steel pipe sheet pile is shown, (a) is sectional drawing, (b) is a perspective view. The impact of the coefficient T _l is on the drainage effect is a graph showing the relationship between the distance X from the drainage function sheet pile front of residual excess pore water pressure ratio R _u and sheet pile. Is a graph showing the relationship between the residual excess pore water pressure ratio R _u and coefficient T _l drainage function sheet pile front. (a), (b) is the graph which showed the relationship between the aperture ratio in the analysis result about the installation space | interval P = 800mm and 1200mm of a drainage material, and the water pressure reduction distance from the sheet pile front surface with a drainage function, respectively. It is a graph showing the relationship between the residual excess pore water pressure ratio R _u width and drainage function sheet pile front of the drainage member. (a) and (b) are coefficients T _l = 100 and 400, respectively, the installation intervals of the drainage members are P = 800 mm, 1000 mm and 1200 mm, the width of the drainage members is W = 250 mm, and the aperture ratio α is α = 1 to 1. it is a graph showing the relationship between the excess pore water pressure R _u and the opening ratio α residual in the analysis results when set to 100%. (a), (b) is a perspective view for demonstrating the ratio which the drainage member occupies for the sheet pile wall projection area, (b), (c) is a conceptual diagram of the distance (water pressure reduction distance) where the drainage effect reaches. . Is a graph showing the relationship between the wall projected area ratio β and residual excess pore water pressure R _u drainage member was examined by drainage analysis (water pressure reducing distance). Is a graph showing the relationship between the excess pore water pressure ratio R _u of the front position of the wall projection area ratio β and drainage member of the drainage member. The width of the drainage member W = 200mm, 250mm, in the case of a 300 mm, is a graph showing the relationship between the residual excess pore water pressure ratio R _u wall projected area ratio and drainage function sheet pile front of the drainage member. Drain member is a graph showing the relationship between the excess pore water pressure ratio R _u drainage member front and length R is not installed. It is sectional drawing which shows the condition of the sheet pile wall at the time of assuming that a 200 mm width drainage member is installed in a sheet pile in a U-shaped steel sheet pile. It is sectional drawing which shows the condition of the sheet pile wall at the time of assuming that the drainage member of 200 mm width is installed in a sheet pile in a hat-type steel sheet pile. Drainage analysis results under conditions of drainage member installation interval P = 1200 mm, length R = 1000 mm where drainage member is not installed in the wall direction, drainage member width W = 200 mm, opening ratio α = 5%, coefficient T _l = 100 It is the graph which showed. (a), (b) is a perspective view which shows embodiment in the case of installing continuously the sheet pile which provided the opening hole in the sheet pile main body, respectively, and making it a sheet pile wall. It is a graph which shows the relationship between an aperture ratio and a flow ratio. (a), (b) is a horizontal sectional view as explanatory drawing regarding the installation position of a drainage member. It is sectional drawing which shows the example of the mat-shaped resin net-like structure as a drainage member. (a), (b) is the figure of the punching metal and expanded metal as an example of the protection board which provided the water-permeable hole, respectively. It is a perspective view which shows the example of the shape of a guard plate, and the attachment method to a sheet pile. (a)-(d) is sectional drawing which shows the other example of the shape of a guard plate, and the attachment method to a sheet pile, respectively. (a), (b) is sectional drawing which shows the other example of the attachment method of the protection board by a stop member, respectively. (a)-(d) is explanatory drawing which shows the example of arrangement | positioning of the sheet pile wall with a drainage function with respect to the structure installed on a liquefiable ground, respectively.

  Hereinafter, specific embodiments, principles, and effects of the present invention will be described in relation to each claim with reference to the drawings. Note that the present invention is not limited to the embodiments described below.

  The sheet pile with drainage function according to claim 1 is a sheet pile with drainage function in which a drainage member is provided along the longitudinal direction of the sheet pile having an effective width of 500 mm or more, and the member opening ratio of the drainage member is 5% or more, and the drainage member The width of is not less than 170 mm.

  As the steel sheet pile, a U-shaped steel sheet pile having an effective width of 400 mm has been mainly used so far. As shown in FIG. 1, in recent years, the steel sheet piles 1 and 2 have been increased in cross section, the material cost is reduced due to the reduction in the weight of the steel material per unit length, and the construction is accompanied by the reduction in the number of placements per construction extension. Construction costs are being reduced by reducing costs.

  Even if the weight of the steel material per unit length is reduced, the cross-section is made large, so it can exhibit the same performance as a wall body compared to conventional steel sheet piles, and the liquefied ground loses rigidity. Even if deformation occurs, the ability to resist it is maintained.

  Therefore, by applying a steel sheet pile having a relatively wide effective width of 500 mm or more to the material of the sheet pile with a drainage function, it is possible to construct a wall body having a rational and strong drainage function, which is very effective.

  Moreover, when a stronger wall body is required, as shown in FIG. 2 and FIG. 3, the drainage function can be achieved by combining the steel sheet pile with various members including H-shaped steel 4, steel sheet pile, steel pipe, and other steel materials. It is also possible to improve the cross-sectional performance as the wall body having.

  It is also effective to install the drainage member 3 on a steel pipe type sheet pile 5 (hereinafter referred to as a steel pipe sheet pile) having an effective width of 500 mm or more to construct a wall body with a drainage function. The steel pipe sheet pile 5 is a steel material having a cross section in which a joint is installed on the steel pipe and exhibiting a very large cross-sectional performance.

Next, the examination result about the optimal arrangement | positioning of a drainage member is shown.
As described above, in the normal state, by providing about 1% of water perforated area on the sheet pile wall body with water passage holes, the amount of water permeation in the normal state can be secured by about 90%. The smooth flow of water is not hindered, and the problems of well drainage and water level reduction behind the wall, which have been problems in the past, do not occur.

  However, a sheet pile with a drainage function is an important function to dissipate excess pore water pressure generated during an earthquake, and is different from steady-state water flow because it deals with dynamic problems.

  Generally, the region where excess pore water pressure is reduced with the occurrence of an earthquake changes from moment to moment. Since the water pressure does not change in the area where the ground has completely liquefied, the flow of pore water does not occur, the area where excess pore water pressure is reduced rapidly shrinks, and finally the area near the sheet pile with drainage function Only by volume compression of the ground in a narrow range, the pore water flows.

  Therefore, since the dynamic water gradient of the front side of the sheet pile with the drainage function becomes high, it is necessary to increase the opening ratio as compared with the steady state in order to secure the necessary drainage amount related to liquefaction countermeasures. The required aperture ratio was examined by a two-dimensional drainage analysis that incorporated the generation and dissipation of excess pore water pressure in the ground during an earthquake into the permeability analysis in a steady state. The wastewater analysis method is described below.

  As the basic equation for the generation and dissipation of excess pore water pressure in the ground, Equation (1), which considered the accumulation and dissipation of excess pore water pressure used by Seed et al. In the evaluation of gravel drain, was applied. Equation (2) based on the repeated test results of saturated sand under non-drainage conditions by De Alba et al. Was assumed as the generation term of excess pore water pressure.

  From these equations (1) and (2), the governing equations for the generation and dissipation of excess pore water pressure in the ground can be obtained. When this is expressed in a two-dimensional orthogonal coordinate system in the horizontal plane and further dimensionless, Equation (3) is obtained. In addition, the permeation coefficient considering the member opening ratio is considered at the installation position of the drainage member, while the analysis is performed considering the non-drainage boundary at the position where the drainage member is not installed. Evaluation was performed.

u: excess pore water pressure t: time k _s : ground permeability coefficient m _v : ground volume compression coefficient γ _W : unit volume weight a of water a: coefficient determined by sand properties and test conditions N: number of repetitions N _l : non-drainage Number of repetitions until liquefaction in the state N _eq : number of repetitions of equivalent constant-amplitude shear stress wave t _d : duration of earthquake motion σ _vo ': initial effective overload (= u / σ _vo ')
R _u : excess pore water pressure ratio l ₀ : reference length

  In the evaluation of the aperture ratio, the point to be noted is the distance from the front face of the sheet pile with a drainage function at which the excess pore water pressure is reduced. This is a distance that can suppress the complete liquefaction of the ground, and affects the degree of damage to the structure.

  In the analysis, we first examined the effects of ground motion conditions and ground conditions on the generation and dissipation of excess pore water pressure in the ground. As shown in Equation (3), the generation and dissipation of excess pore water pressure in the ground depends on the ground motion and ground conditions.

Equation (4) shows what replaces these parameters with one numerical value. Analysis and evaluation are performed using the _Tl value set here. In addition, the reference length l _o for calculating T _l is set to l _o = 1 cm here.

  First, in order to see the effects of ground motion conditions and ground conditions, as a complete drainage boundary condition with an opening ratio of 100% (image of drainage members installed in the entire length in the sheet pile wall direction and the member opening ratio of the drainage members being 100%) The following analysis was performed.

The impact of the coefficient T _l is on the drainage effect, in Figure 4 the relationship between the distance X from the drainage function sheet pile front of residual excess pore water pressure ratio R _u and sheet piles, residual excess pore water pressure ratio of sheet pile front with draining function R _u FIG. 5 shows the relationship between and the coefficient T _l .

The residual excess pore water pressure ratio R _u is a numerical value indicating that the ground is completely liquefied when R _u = 1.0, and here, the time until R _u = 0.95 is described. . As shown in FIG. 4, the larger the T _l , the wider the range of drainage effect, the smaller the excess excess pore water pressure ratio at the front of the sheet pile with drainage function, and the difference in drainage effect around T _l = 100 Is seen.

  In general, the sheet pile with a drainage function is often installed at a position about 1 to 2 m away from the structure in consideration of construction conditions and the like. When applying a sheet pile with a drainage function as a countermeasure for liquefaction of the joint groove, it is important for reducing damage to the joint groove to suppress the liquefaction of the ground between the sheet pile with the drainage function and the joint groove.

Even if T _l = 100 or less, the increase in excess pore water pressure near the sheet pile with drainage function is suppressed, so that the effect as a countermeasure for the structure is exhibited. However, T _l = about 100 or more is necessary for the sheet pile with drainage function. It is considered that the condition is more suitable, and it is considered that the structure can be more effectively taken under this condition.

Next, the influence of the member opening ratio on the drainage effect was examined. The above-mentioned coefficient T _l concerning the ground motion conditions and ground conditions is set to T _l = 100, 400. As an example, the drainage material width W = 250 mm, the drainage material installation interval P = 800 mm, 1200 mm, and the aperture ratio α are analyzed parameters. The analysis results in this case are shown in FIGS. 6 (a) and 6 (b). Here, the analysis was performed by replacing the aperture ratio α with the ratio of the hydraulic conductivity of the ground part and the drainage material installation part.

6 (a) and 6 (b) show the relationship between the aperture ratio and the water pressure reduction distance from the front face of the sheet pile with a drainage function. The greater the aperture ratio, the greater the water pressure reduction distance. Under both conditions of T _l = 100 and 400, the water pressure reduction distance tends to be abruptly shortened with an aperture ratio of about 5% as a boundary. there were. Further, under the condition of T _l = 400, even if the aperture ratio is reduced to 1%, the water pressure reduction distance is secured about 2.5 m.

  Normally, considering that the installation position of the sheet pile with drainage function is about 1 to 2 m from the structure, the analysis condition can be expected to have a sufficient drainage effect even with an aperture ratio of about 1%. Conceivable. Moreover, even if it changed the installation space | interval P of the drainage member, the same tendency was seen respectively.

From these analytical results, under the conditions of severe T _l = 100 of ground motion, ground conditions, aperture ratio is In consideration of influence on the pressure reduction distance, the drainage member aperture ratio drainage function sheet piles to be 5% or more If the aperture ratio is 5% or more, it is considered that a water pressure reduction distance that is not so different from that when the aperture ratio is 100% is secured, and that it sufficiently functions as a countermeasure for the structure.

  Next, the influence of the width of the drainage member on the drainage effect was examined.

As analysis conditions, the width of the drainage member was set to W = 50 mm to 350 mm, the coefficient T ₁ = 100, the installation interval P of the drainage member P = 800 mm, and the aperture ratio α = 5%. The analysis results are shown in FIG.

Figure 7 shows the relationship between the residual excess pore water pressure ratio R _u width and drainage function sheet pile front of the drain member, as a boundary width W = 170 mm of the drain member, the gradient of the residual excess pore water pressure ratio R _u changed.

  Therefore, it is considered desirable to make the width of the drainage member W = 170 mm or more in order to exhibit the function of liquefaction countermeasures more effectively, and the width W = 200 mm, which is a generally available drainage member size. By setting it as the above, versatility is high and the sufficient drainage effect can be anticipated.

  On the other hand, the drainage effect can be expected as the width of the drainage member is larger. However, if the width is too large, the drainage member cost increases, which is irrational. Therefore, the width of the drainage member is desirably about W = 200 to 350 mm.

  According to a second aspect of the present invention, in the sheet pile with a drainage function according to the first aspect, the member opening ratio of the drainage member is 10% or more.

Using an analysis technique described above, the aperture ratio is as effects on drainage effect was studied the relation between the residual excess pore water pressure R _u and aperture ratio of the sheet pile front with draining function alpha.

As analysis conditions, coefficient T _l = 100, 400, drainage member installation intervals P = 800 mm, 1000 mm, 1200 mm, drainage member width W = 250 mm, and aperture ratio α set to α = 1-100%. did.

As an analysis result shown in FIG. 8 (a) the relationship between the residual excess pore water pressure R _u and aperture ratio alpha, shown in (b).

  Both the front surface of the drainage member and the central position between the drainage members changed the gradient of the residual excess pore water pressure ratio with the opening ratio α = about 10% as a boundary. The same tendency was seen regardless of the installation interval of the drainage members.

  In the previous analysis, it was confirmed that the drainage effect is hardly impaired and the function of liquefaction countermeasures can be effectively exhibited if the opening ratio α is about 5% or more with respect to the water pressure reduction distance.

In order to make liquefaction countermeasures function more effectively, it is desirable to keep the residual excess pore water pressure ratio R _u at the front surface of the drainage member of the sheet pile with drainage function to R _u = 0.5 or less. , the relationship of the residual excess pore ratio R _u of the drainage member front position and the aperture ratio alpha in T _l = 100 ground motion, ground conditions severe shown in FIG. 8 (a), the aperture ratio alpha = about 2.5% or more and It is considered desirable to do so.

  In other words, if the opening ratio α set from the previous examination result is 5% or more, it is considered that the function of the liquefaction countermeasure can be effectively exhibited. To expect a higher countermeasure effect, the opening ratio α = It is desirable that it is 10% or more, and if this is satisfied, the residual excess pore water pressure ratio at the front surface of the drainage member can be greatly reduced.

  Further, if the opening ratio α = 10% or more, the water pressure reduction distance is expanded more than when the opening ratio α = 5%, and the function of liquefaction countermeasures is more effectively exhibited. Further, if the opening ratio α = 20% or more, the residual excess pore water pressure at the front surface of the drainage member is almost eliminated, which is almost equal to the ideal condition of the opening ratio α = 100%. In addition to this, since the water pressure reduction distance is increased, the function of liquefaction countermeasures can be exhibited very effectively.

  When the sheet pile with a drainage function according to claim 3 is installed by continuously installing the sheet pile with the drainage function according to claim 1 or 2, the ratio of the drainage member to the projected area of the sheet pile wall body is 15%. This is a feature.

  Here, the ratio to the wall projection area is a projection in which the drainage member 3 is installed in the wall direction within the range where the drainage member 3 is installed in the longitudinal direction of the sheet piles 1 and 2, as shown in FIG. It represents the ratio that the area occupies per unit area.

FIG. 10 shows the relationship between the wall projected area ratio β of the drainage member 3 examined by the drainage analysis and the residual excess pore water pressure R _u (water pressure reduction distance). Here, the evaluation of the residual excess pore water pressure R _u in spaced 50cm from the drainage member front face of the sheet pile position.

This is because, as mentioned above, the sheet pile with a drainage function is often installed at a position about 1 m away from the structure, and suppressing the liquefaction of the ground between the structure and the sheet pile is effective as a countermeasure for the structure. Is. Therefore, as an evaluation with the average excess pore water pressure value of the ground between the structure and the sheet pile, the excess pore water pressure value at a position of 50 cm from the sheet pile was used. In this analysis, the aperture ratio α of the drainage member was set to α = 100% in order to clarify the influence of the coefficient T _l = 100 and the wall projected area ratio β.

From the analysis results shown in FIG. 10, little the value of the wall projected area ratio beta <At 15% excess pore water pressure ratio R _u changes, beta = in the range of beta ≧ 15% of the boundary 15%, depending on the beta value The excess pore water pressure ratio was reduced. From this, it was confirmed that setting the wall projected area ratio β to 15% or more is effective in exerting the function of liquefaction countermeasures.

  According to a fourth aspect of the present invention, in the sheet pile with a drainage function according to the third aspect, the ratio of the drainage member to the sheet pile wall projection area is 20% or more.

  If attention is paid to the flow rate of drainage from the ground toward the drainage member, the lower the dynamic water gradient at the front surface of the drainage member, the smaller the required drainage flow rate, and the smaller the cross-sectional area of the drainage member. For this purpose, it is necessary to make the excess pore water pressure ratio at the front surface position of the drainage member as small as possible.

The relationship between the excess pore water pressure ratio R _u of the front position of the wall projection area ratio β and drainage member of the drainage member illustrated in FIG. 11. In this analysis, in order to evaluate the coefficient T _l = 100 and the excess pore water pressure ratio at the front surface position of the drainage member, the drainage member opening ratio α was set to α = 5%.

From the analysis results shown in FIG. 11, the wall projection area ratio beta ≒ 20% as a boundary, the gradient of the excess pore water pressure ratio R _u at the front position of the drainage member is changed.

  From the analysis results described above, it has been confirmed that by setting the wall projection area ratio β ≧ 15% of the drainage member, the function of liquefaction countermeasures can be effectively exhibited and superior to the countermeasures for structures. By setting the wall projected area ratio β ≧ 20%, the excess pore water pressure ratio at the front surface position of the drainage member is effectively reduced, the required sectional area of the drainage member is reduced, the member cost is reduced, and the construction cost is reduced. Construction costs can be reduced by reducing the resistance from the ground.

  Claim 5 is characterized in that when a sheet pile with drainage function according to claims 1 to 4 is continuously installed to construct a sheet pile wall, the length in the wall direction in which no drainage member is installed is 1.0 m or less. To do.

  When the drainage member is installed on the sheet pile wall, even if the drainage member occupies the same ratio to the sheet pile wall area, the drainage member with a small width is installed at a close interval, and the drainage member with a large width is a loose interval. It is considered that there is a difference in drainage effect from the case where it is installed at the site.

An example of drainage analysis is shown in FIG. This shows the width of the drain member W = 200 mm, 250 mm, in the case of a 300 mm, the relationship between the residual excess pore water pressure ratio R _u wall projected area ratio and drainage function sheet pile front of the drainage member . As a result, it was confirmed that if the drainage members are installed at the same wall projected area ratio, it is more effective to install the drainage members having a small width at a close interval.

  When sheet piles are installed continuously and used as sheet pile walls, the drainage member has a smaller width in the wall direction than the installation of a wider drainage member at one location and the installation interval is increased as an effective installation method of the drainage member. It was clarified in the previous examination results that it is effective to install the sparsely.

  On the other hand, when installing drainage members with small widths at close intervals so that the wall projection areas of the drainage members are equal, if the width of the drainage members is too small, the quantity of drainage members will increase accordingly, and Processing costs increase and become irrational. Therefore, it is considered effective and rational to install drainage members with appropriate widths on the sheet pile wall at appropriate intervals. To do so, install drainage members in the wall direction, which is the interval between the drainage members. It is important to limit the length that does not.

Therefore, the coefficient T _l = 100, the drainage member opening ratio α = 5%, the drainage member width within the range of W ≧ 170 mm and the highly versatile size W = 200 mm, and the length R where the drainage member is not installed Drainage analysis was performed using the parameters. Analysis result shows the relationship between the excess pore water pressure ratio R _u drainage member front and length R drainage member is not installed in FIG. 13.

As shown in FIG. 13, the length R = 1.0 m drainage member is not installed (1000 mm) as a boundary, the gradient of the excess pore water pressure ratio R _u that changes was confirmed. From this, it is thought that the function of a countermeasure against liquefaction can be effectively exhibited by setting the length R where the drainage member is not installed to 1.0 m or less.

  Currently, the effective widths of sheet piles with an effective width of 500 mm or more that are generally used are 500 mm, 600 mm, and 900 mm. Therefore, considering the shape characteristics of the sheet pile, for example, considering that the drainage member having a member width of 200 mm or more is installed in the web portion of the sheet pile, as shown in FIG. 14, the drainage installed adjacent to the wall direction. The member installation interval P is a length P = 2L, which is twice the sheet pile effective width L. Further, considering the width of the drainage member, the length R at which the drainage member is not installed in the wall direction is a value R = 2L−W obtained by subtracting the drainage member width W from the value obtained by doubling the sheet pile effective width L.

  There are U-shaped and hat-shaped sheet piles. Currently, sheet piles having an effective width of 500 mm and 600 mm are generally U-shaped, and sheet piles having an effective width of 900 mm are generally hat-shaped. Here, the state of the sheet pile wall when it is assumed that the drainage member having a width of 200 mm set as the minimum required width of the drainage member is installed on the sheet pile is shown in FIGS.

  Here, it is assumed that the drainage member 3 is installed in the web part of each sheet pile 1,2. In the U-shaped steel sheet pile with an effective width of 500 mm, the installation interval of drainage members is 1000 mm, the length where the drainage member is not installed is 800 mm, and in the U-shaped steel sheet pile with an effective width L = 600 mm, the installation interval P of the drainage members is 1200 mm, The length R in which no is installed is 1000 mm.

  On the other hand, the hat-type steel sheet pile with an effective width L = 900 mm has a structure in which the drainage member is installed only on one side of the wall due to the hat-shaped characteristics, the installation interval P between drainage members is 900 mm, and the length R where the drainage member is not installed is 700 mm. In the condition of installing the drainage member on the sheet pile web part, the installation interval P of the drainage member is 1200 mm at the longest, and considering the minimum width W = 200 mm of the drainage member, the interval at which the drainage member is not installed in the wall direction is R = 1000 mm (1.0 m) or less.

  From these, it is considered that it is very effective to apply a steel sheet pile having an effective width of 500 mm or more that is generally used as a target of a sheet pile with a drainage function.

In order to confirm the validity of the above-described distance P between the drainage members P = 1200 mm and the length R = 1000 mm (1.0 m) at which the drainage members are not installed in the wall direction, the drainage member width W = 200 mm and the aperture ratio α = 5 %, Drainage analysis was performed under the conditions of a coefficient T _l = 100. From the analysis results shown in FIG. 16, the residual excess pore water pressure ratio R _u at the front surface of the drainage member is R _u = 0.32 ≦ 0.5, and it was confirmed that a sufficient drainage effect can be obtained under the set conditions. .

Claim 6 is a sheet pile with a drainage function according to claims 1 to 5, wherein the drainage member has a sectional area of 20 cm ² or more, and the drainage member has a thickness in the direction perpendicular to the axis of 10 mm or more. To do.

The drainable flow rate Q ₁ of the drainage member is generally evaluated by equation (5). On the other hand, the inflow amount Q ₂ from the ground is evaluated by the equation (6). Here, the hydraulic gradient at the front surface of the drainage member is given by equation (7).

Member cross-sectional area of the drain member, the formula (5), equation (6), the range is required of the formula (8) from the relationship of the expression (7), a result of various studies 20 cm ² or more drainage member cross It is desirable to have an area.

On the other hand, if the cross-sectional area of the drainage member is too large, resistance from the ground will act on the drainage member at the time of placing, making construction difficult and increasing the construction cost, and increasing the drainage member cost will be irrational. . Therefore, member cross-sectional area of the drain member, it is desirable to 20cm ² ~200cm ² about.

It is necessary to satisfy Q ₁ ≦ Q ₂ .

Q _1: drainage member can wastewater volume Q _2: water is drained from the ground V: flow rate A _t: cross-sectional flow area A _s of the drain member: drainage area from soil N: Roughness Factor R: Dosui radius i: Hydrodynamic gradient

  In addition, since the drainage member is installed in the ground, the earth pressure in the horizontal direction acts on the drainage member according to the depth in the underground part, and the drainage member needs to have strength that can withstand the earth pressure. Become.

When the earth pressure in the horizontal direction acts on the drainage member, the drainage member is compressed, and the water flow cross-sectional area of the drainage member is reduced accordingly. Therefore, the thickness of the drainage member in the direction perpendicular to the axis is desirably 10 mm or more.

  On the other hand, if the thickness of the drainage member in the direction perpendicular to the axis is too large, there is a concern that the drainage member will have a resistance force from the ground at the time of placing, and the drainage member cost will increase. Be irrational. Therefore, the thickness of the drainage member in the direction perpendicular to the axis is preferably about 10 to 100 mm.

  The sheet pile with a drainage function according to claim 7 has a wall projection area ratio of 0.5% or more on the sheet pile main body when the sheet pile with drainage function according to claims 1 to 6 is continuously installed to construct a sheet pile wall. An opening hole for ensuring a smooth flow of groundwater is provided, and a sheet pile with a drainage function is provided with a water permeability function.

  As shown in Figs. 17 (a) and 17 (b), a sheet pile with openings 7 and 8 provided in the sheet pile main bodies 1 and 2 is continuously installed to form a sheet pile wall, thereby ensuring a smooth flow of groundwater and the like. This solves the problem of well withering and water level drop behind the wall. The position at which the opening hole is provided in the sheet pile is not limited to a sheet pile web portion or a flange portion, and the shape of the hole is not limited to a circle, an ellipse, or a rectangle.

  Moreover, as shown in FIG.17 (b), by providing the opening hole 8 in the projection range in which the waste_water | drain member 3 is installed in the sheet pile 2, the water-permeable hole for not inhibiting the flow of groundwater etc. normally, It can be expected to function as a drainage hole to dissipate excess pore water pressure generated during an earthquake. Thereby, the function of the countermeasure against liquefaction is exhibited also in the ground on the opposite side where the drainage member 3 is installed, which is very effective.

  On the other hand, if the wall projected area ratio of the opening holes 7 and 8 provided in the sheet pile becomes too large, it is effective in terms of not inhibiting the flow of groundwater, but there is a concern that the sheet pile performance according to the opening holes 7 and 8 is deteriorated. And the processing cost for providing the opening hole may increase and become unreasonable.

  Further, as shown in FIG. 18, if the area ratio of the opening hole is about 2.0%, about 95% of the water permeation amount in the normal state is ensured. Is preferably about 0.5 to 2.0%.

  According to an eighth aspect of the present invention, in the sheet pile with drainage function according to the first to seventh aspects, the position where the drainage member is installed is a sheet pile web portion.

  Due to the shape characteristics of the sheet pile, the web part is flat and the horizontal length is longer than other parts, the installation of the drainage member is easy, and the processing cost can be suppressed. Moreover, since it is flat in the horizontal direction, as shown in FIG. 19A, the drainage member width can be fully utilized when the drainage member 3 is installed.

  If the drainage member 3 is installed on the flange portion, as shown in FIG. 19B, the projection area in the wall direction is reduced even if the drainage member 3 having the same width is installed, and the drainage member 3 is projected on the wall. The percentage of the area is reduced.

  Therefore, in order to increase the projected area in the wall direction, it is necessary to install a drainage member with a wider width, which increases the drainage member cost and also increases the resistance from the ground during construction, making construction difficult. This increases the construction cost and is irrational.

  By making the installation location of the drainage member 3 a sheet pile web part, it is possible to construct an effective and rational sheet pile wall with a drainage function.

  According to a ninth aspect of the present invention, in the sheet pile with drainage function according to the first to eighth aspects, the drainage member is installed only above the lower end of the layer where liquefaction is a concern during an earthquake.

  This is to limit the installation position of the drainage member in the longitudinal direction of the sheet pile. By setting the installation position only above the lower end of the layer where liquefaction may occur during an earthquake, the drainage member cost can be reduced and the construction cost can be reduced. Can be reduced and is reasonable.

  Claim 10 is a sheet pile with a drainage function according to claims 1 to 9, wherein the drainage member is a mat-like resin net-like structure, and intrusion of earth and sand while ensuring water permeability on the resin net-like structure. It is characterized in that a filter for preventing is provided.

  Although the drainage member is not particularly limited, by using a mat-like resin network structure 3a as shown in FIG. 20, it is easy to install on the sheet pile, and the processing cost can be reduced, and the resistance from the ground during construction can be reduced. It can be minimized and construction costs can be reduced.

  Furthermore, by providing the filter 11 for preventing the intrusion of earth and sand while ensuring water permeability on the resin network structure 3a, the resin network structure 3a can be prevented from being clogged and a sufficient drainage effect is exhibited. .

  The eleventh aspect is characterized in that in the sheet pile with drainage function according to the tenth aspect, a protective plate having a water permeability hole larger than the mesh of the filter is further provided on the filter for preventing damage to the filter. It is.

  A protective plate provided with water-permeable holes as shown in FIGS. 21 (a) and 21 (b) on the filter (FIG. 21 (a) is an example of a punching metal 12a and FIG. 21 (b) is an example of an expanded metal 12b). By providing, it is possible to prevent the drainage member and the filter material from being damaged at the time of placing.

  The permeation holes provided in the protection plate are larger than the mesh of the filter, and the larger the permeation hole, the more sufficient water drainage is ensured in the event of an earthquake, so the area of the permeation hole is about 10% or more of the area of the protection plate It is desirable that

  On the other hand, if the water-permeable holes are too large, the processing cost for providing the water-permeable holes will increase, and if the area where the filter comes into contact with earth and sand becomes large during placement, it will not make sense to provide a protective plate, which is irrational. . Therefore, it is desirable that the area of the water permeable holes provided in the protection plate is about 10% to 50% of the area of the protection plate.

  Moreover, the water-permeable hole provided in a guard plate should just open on the surface of the normal line direction at least with respect to the wall direction. Further, the shape and size of the protection plate and the method of attaching to the sheet pile are not limited, and the protection plate may be pulled out after installing the sheet pile with drainage function on the ground.

Examples of the shape of the protection plate 12 and the method of attaching it to the sheet pile are shown in FIGS.
As shown in FIG. 23 (a), a protective plate 12 formed of a flat plate such as an iron plate is installed between the flanges of the sheet pile 1, and as shown in FIG. 23 (b), a concave type covering the drainage member 3 is provided. There are a method of installing the protection plate 12 on the web portion of the sheet pile 1 and a method of installing a B-shaped protection plate 12 surrounding the drainage member 3 on the web portion of the sheet pile 1 as shown in FIG.

  23 (b) and 23 (c) can be formed by bending one flat plate or combining several flat plates. FIG. 23 (d) shows an example of attachment of the protection plate 12 in the case where the opening hole 8 as a water permeable hole is provided in the back surface of the drainage member.

  Further, the protection plate 12 is not necessarily fixed to the sheet pile over the entire length, and as shown in FIGS. 24 (a) and 24 (b), stop members provided on the sheet piles 1 and 2 discretely or over the entire length. 13 may be fixed. Furthermore, if it is fixed with a stop member such as a guide rail, the protective plate is not easily detached, and the installation is easy, so that the construction cost can be reduced.

  The stop member 13 and the drainage member are not necessarily fixed. The stopper member 13 may be of any material and shape, and can be formed with a cost advantage. As an example, it is conceivable to provide the stop member with a flat plate or round steel.

  Claim 12 is a sheet pile with a drainage function according to claims 1 to 11, wherein the drainage member and the sheet pile are discretely fixed along the distal end portion of the drainage member and the sheet pile longitudinal direction. It is.

  The total length of the drainage member is not necessarily fixed to the sheet pile, and the installation range is not limited. Moreover, the installation method and the member used for installation are not limited.

  By fixing and protecting the front end portion of the drainage member to the sheet pile, it is possible to prevent intrusion of earth and sand from the front end portion of the drainage member, and it is possible to suppress damage to the drainage member at the time of placing. Moreover, by fixing in the sheet pile longitudinal direction discretely, construction becomes easy and construction cost is suppressed. Further, the processing cost is reduced as compared with the case where the entire length is fixed.

  The sheet pile wall structure with a drainage function according to claim 13 is constructed by continuously installing and constructing a sheet pile with a drainage function according to claims 1 to 12.

  A sheet pile wall structure with a drainage function according to claim 14 is used as a sheet pile cutoff for a structure installed on a liquefiable ground, and at least the drainage is disposed inside the sheet pile cutoff where the structure exists. The member is positioned.

  As shown in FIG. 25 (c), by installing the drainage member C only on the structure A side of the sheet pile wall B, the drainage member cost and the construction cost can be reduced, and the structure can be rationalized. To take measures.

  By not installing the drainage member C on the opposite side of the structure A, at the time of an earthquake, the generation of excess pore water pressure near the sheet pile on that side is not reduced, and there is a concern that the liquefiable ground will be liquefied. However, the ground on the side of the structure A surrounded by the sheet pile with the drainage function is suppressed from being liquefied, and a sufficient countermeasure effect can be expected.

  In particular, in measures such as common grooves, it is important to take measures against liquefaction of the ground between the sheet pile and the common groove. As shown in FIG. 25 (c), at least the drainage member on the structure A side (inside the sheet pile cut-off) If C is installed, the function of liquefaction countermeasures can be demonstrated effectively and rationally.

  The installation position of the drainage member C is not particularly limited. When implementing countermeasures against liquefaction of a structure that is long in the longitudinal direction such as a common groove, the drainage member C is installed on both the inside and outside of the sheet pile wall B in a certain section. (See Fig. 25 (a)), in some sections, drainage members C are installed only inside the sheet pile cut-off, and in certain sections, one side sheet pile wall B is on both the inside and outside sides, and one side sheet pile wall B is on the inside only. Select a reasonable arrangement according to the performance required for the structure A, such as installing C (see Fig. 25 (b)) and not installing any drainage member C in some sections (see Fig. 25 (d)). Is possible.

DESCRIPTION OF SYMBOLS 1 ... U-shaped steel sheet pile, 2 ... Hat-shaped steel sheet pile, 3 ... Drainage member, 3a ... Three-dimensional network structure made of resin, 4 ... H-shaped steel, 5 ... Steel pipe sheet pile, 6 ... Steel pipe, 7 ... Opening hole, 8 ... Opening hole,
DESCRIPTION OF SYMBOLS 11 ... Filter, 12 ... Guard plate, 12a ... Punching metal, 12b ... Expanded metal, 13 ... Stopping member,
A ... Structure, B ... Sheet pile wall, C ... Drainage member

Claims (14)

  In the sheet pile with a drainage function in which a drainage member is provided along the longitudinal direction of the sheet pile having an effective width of 500 mm or more, the drainage member has an opening ratio of 5% or more, and the drainage member has a width of 170 mm or more. A sheet pile with drainage function.   The sheet pile with a drainage function according to claim 1, wherein a member opening ratio of the drainage member is 10% or more.   When the sheet pile with drainage function according to claim 1 or 2 is continuously installed to construct a sheet pile wall, the drainage function is characterized in that a ratio of the drainage member to the sheet pile wall projection area is 15% or more. Attached sheet pile.   4. The sheet pile with drainage function according to claim 3, wherein a ratio of the drainage member to a sheet pile wall projected area is 20% or more.   When the sheet pile with a drainage function according to any one of claims 1 to 4 is continuously installed to construct a sheet pile wall, the wall direction length in which the drainage member is not installed is 1.0 m or less. Characterized sheet pile with drainage function. The member cross-sectional area of the drainage member is 20 cm ² or more, and the thickness of the drainage member in the direction perpendicular to the axis is 10 mm or more. With drainage function according to any one of claims 1 to 5, Sheet pile.   When the sheet pile with drainage function according to any one of claims 1 to 6 is continuously installed to construct a sheet pile wall, the sheet pile main body is provided with an opening hole having a wall projection area ratio of 0.5% or more. A sheet pile with a drainage function.   The sheet pile with a drainage function according to any one of claims 1 to 7, wherein a position where the drainage member is installed is a sheet pile web portion.   The sheet pile with drainage function according to any one of claims 1 to 8, wherein the drainage member is installed only above the lower end of the layer where liquefaction is a concern during an earthquake.   2. The drainage member is a mat-like resin network structure, and a filter for preventing intrusion of earth and sand while ensuring water permeability is provided on the resin network structure. The sheet pile with a drainage function according to any one of? 9.   11. A sheet pile with a drainage function according to claim 10, further comprising a protective plate having a water permeable hole larger than the mesh of the filter for preventing damage to the filter on the filter.   The said drainage member and a sheet pile are fixed discretely along the front-end | tip part of a drainage member, and a sheet pile longitudinal direction, The sheet pile with a drainage function as described in any one of Claims 1-11 characterized by the above-mentioned.   A sheet pile wall structure with a drainage function, wherein the sheet pile with a drainage function according to any one of claims 1 to 12 is continuously installed and constructed. The drainage function according to claim 13, wherein the drainage member is used as a sheet pile cutoff for a structure installed on a liquefiable ground, and at least the drainage member is positioned inside a sheet pile cutoff where the structure exists. With sheet pile wall structure.