JP5669192B2 - Quay structure or revetment structure - Google Patents

Description

  The present invention relates to a quay structure or a revetment structure.

  A construction method that uses light-mixed soil for the backfill soil of a quay or revetment is known as a light-mixed soil treatment method (Non-Patent Document 1), and this method uses a lightweight material for the backfill soil. Earth pressure can be reduced, and the horizontal force during an earthquake can be reduced. In addition, a slope bottom method for increasing resistance to horizontal force using a caisson bottom as a slope on a gravitational quay or revetment is known (Patent Document 1). Furthermore, it is known that the resistance force against the horizontal force is increased in the artificial wall by the ground anchor (Patent Document 2).

JP 09-221730 A JP 2009-46817

Coastal Development Technology Library No.3 “Lightweight Mixed Processing Earth Construction Technology Manual for Ports and Airports” (April 1999) Issued Coastal Development Technology Research Center

  The light-weight mixed processing earth method has a problem that the material cost becomes high because a lightening material such as foam beads is used. In addition, the oblique bottom construction method can reduce the caisson width, but the bottom surface reaction force increases, so that it is necessary to strengthen the foundation ground and foundation mound, resulting in high construction costs. In the structure using the ground anchor, the anchor length becomes long when the supporting ground is deep.

  The present invention provides a quay structure or a revetment structure capable of reducing the required weight of a gravity-type quay and revetment and the cross-sectional performance of a sheet pile used for a sheet pile quay and revetment while maintaining stability against earthquakes at the quay and revetment. The purpose is to do.

  In order to increase the stability of the quay and revetment against earthquakes, the inventor pays attention to the water level difference between the water level on the sea side of the quay and revetment and the water level on the rear side of the land side of the quay and revetment, and the water pressure on the sea side. The idea is that the required weight of gravity piers and revetments and the cross-sectional performance of sheet piles used for sheet pile berths and revetments can be reduced while maintaining stability against earthquakes at the quay and revetments. This has led to the present invention.

  The principle of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view (a) schematically showing a normal structure at a quay / revetment and a similar cross-sectional view (b) showing a case where the water level on the back surface is lowered in the structure of FIG. 1 (a).

  The water pressure corresponding to the difference (water level difference) between the water level of the rear side R on the shore side and the water level of the front side F on the sea side acts on the quay (or revetment) dam body as shown in FIG. When the residual water level on the land side is higher than the water level on the sea side, the water pressure due to the water level difference acts on the back surface R of the dam body together with the earth pressure. On the other hand, as shown in FIG. 1B, when the water level of the rear side R on the land side is lowered and lower than the water level of the front side F on the sea side, earth pressure acts on the rear side R of the levee body. The water pressure due to the water level difference between the water level on the front surface F and the water level on the back surface R acts on the front surface F of the levee body. Such water pressure acts in the opposite direction to the horizontal force applied to the back surface R of the levee body due to the earthquake motion, so that the resultant horizontal force acting on the dam body due to the earthquake motion can be reduced. Therefore, by using the water level difference between the sea side and the land side of the quay and applying water pressure from the sea side to the land side, the required weight of the gravity quay and revetment is maintained while maintaining the stability of the quay or revetment during an earthquake. And the cross-sectional performance of the sheet pile used for the sheet pile type quay can be reduced.

A quay structure or a revetment structure for achieving the above object is provided with a water shielding part on the back of the quay or the revetment so as to block the groundwater from entering and leaving the surrounding ground, and the water shielding part comprises the groundwater. A sheet material laid so as to cover the ground in order to block entry and exit, and a water permeable material deposited on the sheet material, and an end portion of the sheet material is impermeable to water, A drainage means is installed in the water part, and the water level in the impermeable part is kept lower than the water level of the sea surface in front of the quay or revetment by the drainage means, so that the quay or the revetment has earthquake resistance. .

According to this quay structure or revetment structure, the water impermeable part provided on the land side at the back of the quay or revetment blocks the entrance and exit of groundwater from the surrounding ground, and the water impervious part by a drainage means such as a drain pump. By keeping the water level at the lower level than the sea level at the front of the quay or revetment, the water pressure due to the difference in water level acts on the front of the quay or revetment in the opposite direction to the horizontal force on the back of the dam due to seismic motion. Alternatively, the resultant horizontal force acting on the revetment can be reduced, and therefore the stability against earthquakes at the quay or revetment can be improved . In addition, it is possible to reduce the required weight of the gravity quay and revetment and the cross-sectional performance of the sheet pile used for the sheet pile quay and revetment.

Moreover , it is preferable that the said water-impervious part has a water stop sheet pile, and the said water stop sheet pile is arrange | positioned only a predetermined distance away from the back surface of the said quay or revetment.

  Further, when the quay or revetment is a gravity type by caisson, the sheet material is laid to the upper end of the back or front of the caisson, and a sheet margin is provided so that the sheet material sags at the lower end of the back or front It is preferable. Even if the caisson moves during an earthquake, the sheet material extends at the margin at the lower end of the caisson, so that the sheet material can be prevented from being damaged, and the water imperviousness by the water shielding part can be maintained.

  Moreover, you may make it use the impermeable layer of a raw ground instead of the said sheet material. When there is a water-impermeable layer such as a clay layer on the original ground, the material cost can be reduced by using this instead of the sheet material.

As mentioned above, the quay structure or revetment structure can maintain stability against earthquakes at the quay or revetment due to the water pressure due to the water level difference applied to the back of the quay or revetment, so that the quay or revetment has earthquake resistance. It can be constructed in an earthquake resistant structure.

  According to the quay structure or the revetment structure of the present invention, it is possible to reduce the required weight of the gravity quay / revetment and the cross-sectional performance of the sheet pile used for the sheet pile quay while maintaining stability against earthquakes at the quay / revetment.

It is the same sectional drawing (b) which shows the case where the water level of the back is lowered in the structure of Drawing 1 (a) and the structure of Drawing 1 (a) showing the usual structure in a quay and a revetment. It is sectional drawing for demonstrating the 1st example of the quay structure applied to the sheet pile type quay by 1st Embodiment. It is sectional drawing for demonstrating the 2nd example of the quay structure applied to the sheet pile type quay by 1st Embodiment. It is sectional drawing for demonstrating the 1st example of the quay structure applied to the gravity type quay by a 2nd embodiment. It is sectional drawing for demonstrating the 2nd example of the quay structure applied to the gravity type quay by a 2nd embodiment. It is sectional drawing for demonstrating the 3rd example of the quay structure applied to the gravity type quay by 2nd Embodiment. FIG. 4 or FIG. 5 shows a partial view (a) showing an example in which a sheet margin portion is provided on the water-impervious sheet at the lower end of the back side of the caisson, and an example in which a sheet margin portion is provided on the waterproof sheet at the lower end of the front side of the caisson in FIG. It is a partial figure (b) shown. It is a graph which shows the result of having calculated the fall rate by the water level fall of the horizontal force computed as earth force and water pressure by Coulomb earth pressure type. It is sectional drawing for demonstrating the 3rd example of the quay structure applied to the sheet pile type quay by 1st Embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 2 is a cross-sectional view for explaining a first example of a quay structure applied to a sheet pile quay according to the first embodiment. FIG. 3 is a cross-sectional view for explaining the second example.

  A first example according to the present embodiment is a sheet pile quay structure, and as shown in FIG. 2, this sheet pile quay structure has a water shielding portion 12 on the back surface (land side) of a steel pipe sheet pile 11 placed on the bottom G. And a drainage pump 18 is installed in order to keep the water level H in the impermeable portion 12 below the set water level.

  The set water level in the water-impervious portion 12 is determined in consideration of the amount of water level that can be lowered determined by the strength of the water-impervious material and the drainage capacity of the pump, and the economics of the quay (revetment) structure according to the drop in horizontal force due to the water level drop. It is preferred that

  The water-impervious portion 12 includes a water-impervious sheet 14 laid so as to cover the bottom G, and a water-stop sheet pile 17 placed at a position that is a predetermined distance away from the steel pipe sheet pile 11 in the horizontal direction on the land side (right side in the figure). And a highly water-permeable rubble 13 which is deposited on the water-impervious sheet 14 and is backed by the back surface of the steel pipe sheet pile 11.

The water-impervious sheet 14 covers the bottom G from the bottom G of the steel pipe sheet pile 11 to the bottom G of the bottom of the water stop sheet pile 17, and one end side (sea side) of the water is placed in the bottom G. The other end side (land side) is fixed by the concrete 15 and impermeable, and the other end side (land side) is fixed by the underwater concrete 16 placed on the bottom G of the waterstop sheet pile 17 side. The water-impervious sheet 14 is covered with a protective material 14a as shown in FIG. 9 so that the water-impervious sheet 14 is not damaged even if it touches rubble or the ground. The waterstop sheet pile 17 fills the joint with mortar, applies a water shielding material, and the like so that water does not enter.

  Further, a pipe extends from the drainage pump 18 into the rubble 13 of the water shielding portion 12, and the suction port 18 a at the tip thereof is at a position below the set water level in the rubble 13. Thereby, when the water level H of the water shielding part 12 exceeds the set water level, the water level H of the water shielding part 12 can be constantly kept below the set water level by operating the drain pump 18 to drain water.

  An impermeable pavement 20 is provided on the upper surface of the water-impervious portion 12 to prevent rainwater from entering. Further, the buried soil M is backfilled on the back side (land side) of the water-stop sheet pile 17.

  Since the residual water level (RWL) in the buried soil M and the water level HS of the seawater surface are larger than the water level H of the water shielding part 12, upward or obliquely upward water pressure acts on the water shielding sheet 14, but as described above, The rubble 13 is deposited on the water sheet 14, and the structure is configured to resist the water pressure due to the water level difference by the rubble weight.

The water pressure acting on the water shielding sheet 14 is, for example, 2 tf / m ² when the water level drop is 2 m, so it is necessary to use a sheet material or a water shielding part structure that can withstand the corresponding strength.

  In addition, about water shielding materials, such as a water shielding sheet and a water-stop sheet pile, and a construction method, the technique similar to the water-blocking sheet and water sheet pile used at a waste disposal site can be utilized.

  As described above, in the sheet pile type quay of FIG. 2, the water shielding portion 12 including the rubble 13, the water shielding sheet 14 and the water stop sheet pile 17 is constructed on the back surface of the steel pipe sheet pile 11. Behind the sheet pile quay, the water shielding sheet 14 blocks the groundwater from entering and exiting the sand layer N, the waterstop sheet pile 17 blocks the groundwater from entering and exiting the buried soil M, and the rubble 13 permeates the water well. Thereby, the water level H of the impermeable part 12 can be reduced easily. In this way, the water level lowering range A is constituted by the water shielding portion 12 behind the sheet pile type quay.

  As described above, on the back side of the sheet pile quay, a portion where the groundwater does not flow with respect to the surrounding ground is constructed by the water shielding sheet 14 and the water shut sheet pile 17 of the water shielding portion 12, and within the water level lowering range A. When the water level H rises, the quay structure in which the state in which the water level is lowered can be permanently maintained by keeping the water level H below the set water level by the drainage pump 18.

  Moreover, even if the water level H of the impermeable part 12 may rise due to intrusion of rainwater or the like, the water level H can be easily lowered again below the set water level by draining with the drain pump 18. Thus, by controlling the water level H with the drainage pump 18 so that the water level H in the water level lowering range A is equal to or lower than the set water level, the water level difference between the water level HS of the sea level and the water level H in the water level lowering range A Becomes ΔH (HS−H), and the water pressure due to the water level difference ΔH acts on the front surface of the steel pipe sheet pile 11 constantly.

  As described above, according to the sheet pile type quay structure of FIG. 2, the steel sheet pile is maintained while maintaining the stability of the sheet pile type quay during an earthquake by applying water pressure from the sea side front surface to the land side rear surface. The cross-sectional performance can be reduced and the sheet pile length can be reduced.

  Moreover, since the water-impervious sheet 14 and the water-stop sheet pile 17 have high deformation performance, even if the quay or the ground is displaced due to secular change such as subsidence, the water-blocking portion 12 can be kept water-tight.

  Moreover, it is preferable to monitor the water level H on a daily basis because the water level H in the water level lowering range A rises due to the intrusion of rainwater into the impermeable portion 12 or the infiltration from the sheet pile joint. By draining with the pump 18, the reliability of the earthquake-resistant structure which the quay structure of this embodiment has is improved. If a water level meter is installed in the water shielding unit 12 and it is detected that the water level H has reached the set water level, the drain pump 18 may be automatically driven based on this detection.

  Conventionally, water level lowering methods such as deep well method and well point method that lower the water level with a pump for the purpose of reducing water pressure during earth retaining work in excavation work are known, but these methods are used for temporary work. It is not a technique used for permanent structures.

  Next, the second example according to the present embodiment is a sheet pile type quay structure. As shown in FIG. 3, an impermeable layer such as a viscous soil layer of the original ground is used instead of the impermeable sheet, 2 is different from FIG.

  As shown in FIG. 3, when the raw ground has a viscous soil layer L that is an impermeable layer on the sand layer K, for example, the steel pipe sheet pile 11 is driven from the bottom G, and the steel pipe sheet pile 11 is land side (right side in the figure). The water-stop sheet pile 17 is driven on the viscous soil layer L at a position separated by a predetermined distance in the horizontal direction, and the water permeability is high on the viscous soil layer L between the back surface of the steel pipe sheet pile 11 and the front surface of the water-stop sheet pile 17. Deposit rubble stone 13 and back it up. In this way, the water-impervious portion 22 includes the water-stop sheet pile 17, the viscous soil layer L, and the rubble 13. The water level H in the impermeable portion 22 is constantly kept below the set water level by the drain pump 18.

  As described above, behind the sheet pile quay, a portion where the groundwater does not flow to the surrounding ground by the viscous soil layer L of the water shielding portion 22 and the water stop sheet pile 17 is constructed, When the water level H rises, the quay structure in which the state in which the water level is lowered can be permanently maintained by keeping the water level H below the set water level by the drainage pump 18.

  When there is a water-impermeable layer such as a clay layer on the original ground as shown in FIG. 3, the water-impermeable layer can be used in place of the water-impervious sheet, and the water-impervious sheet can be omitted, so that the material cost can be reduced. It can also be applied to existing quays and revetments if the conditions are satisfied.

  By controlling the water level H within the water level lowering range A of the water shielding portion 22 with the drainage pump 18 so as to be lower than the set water level as in FIG. 2, the water level HS at the sea level and the water level within the water level lowering range A are controlled. The water pressure due to the water level difference ΔH with respect to H constantly acts on the front surface of the steel pipe sheet pile 11.

  As described above, according to the sheet pile type quay structure of FIG. 3, the cross section of the steel sheet pile while maintaining the stability of the sheet pile type quay during an earthquake by applying water pressure from the sea side to the land side as in FIG. Performance can be reduced and sheet pile length can be reduced.

  FIG. 9 is a sectional view for explaining a third example of the quay structure applied to the sheet pile quay according to the first embodiment. The sheet pile type quay structure in FIG. 9 is basically the same structure as in FIG. 2, but the water shielding part 12 is configured by laying a water shielding sheet 14 on the slope of the sand layer N. The same effect as FIG. 2 can be acquired by the sheet pile type quay structure of FIG.

<Second Embodiment>
FIG. 4 is a cross-sectional view for explaining a first example of a quay structure applied to a gravity quay according to the second embodiment. FIG. 5 is a cross-sectional view for explaining the second example. FIG. 6 is a sectional view for explaining the third example.

  The first example according to the present embodiment is a gravity quay structure. As shown in FIG. 4, this gravity quay structure has a caisson 31 installed on a foundation rubble P built on a water bottom G. A water shielding portion 32 is provided on the back surface 31b (land side), and a drainage pump 38 is installed to keep the water level H in the water shielding portion 32 below a set water level.

  As in FIG. 2, the water-impervious portion 32 has a water-impervious sheet 34 laid so as to cover the foundation rubble P and the sand layer N, and a predetermined distance in the horizontal direction from the back surface 31 b of the caisson 31 to the land side (right side in the figure). It consists of a water-stop sheet pile 37 placed in the sand layer N at a distant position, and a highly water-permeable rubble 33 deposited on the water-impervious sheet 34 and backed by the back surface 31b of the caisson 31.

  The water-impervious sheet 34 extends from the back surface 31b of the caisson 31 to the base rubble P at the lower end, the slope of the sand layer N, and a portion higher than the foundation rubble P of the sand layer N on which the waterproof sheet pile 37 is placed. The back surface 31b, the foundation rubble P and the sand layer N are covered. One end 34 b of the water-impervious sheet 34 extends to the upper end of the back surface 31 b of the caisson 31 to be impermeable, and the other end is pressed by the rubble stone 13 at the lower end of the water-stop sheet pile 17 and closely contacts the water-stop sheet pile 17. It has been impervious to water. The water-impervious sheet at the end 34 b may be only the joint portion of the caisson 31. The upper and lower surfaces of the water-impervious sheet 34 are covered with a protective material 34a so that the water-impervious sheet 34 is not damaged even if it touches rubble or the ground. The protective material 34a is omitted on the back surface 31b of the caisson 31, but may be provided.

  Further, a pipe extends from the drainage pump 38 into the rubble 33 of the water shielding portion 32, and the suction port 38 a at the tip thereof is at a position below the set water level in the rubble 33. Thereby, the water level H of the water-impervious portion 32 can be constantly kept at the set water level.

  An impervious pavement 40 is applied to the upper surface of the water-impervious portion 32. In addition, the buried soil M is backfilled on the back side (land side) of the water stop sheet pile 37.

  As described above, behind the gravity quay, a portion where the groundwater does not flow with respect to the surrounding ground is constructed by the water shielding sheet 34 and the water stop sheet pile 37 of the water shielding portion 32, and within the water level lowering range A. When the water level H rises, it is possible to construct a quay structure in which the state in which the water level is lowered lasts permanently by keeping the water level H below the set water level by the drainage pump 38.

  The water level difference between the water level HS in the sea level and the water level H in the water level lowering range A is controlled by the drainage pump 38 so that the water level H in the water level lowering range A of the water shielding part 32 is lower than the set water level. Becomes ΔH (HS−H), and the water pressure due to the water level difference ΔH constantly acts on the front surface 31 a of the caisson 31. Since the water pressure acts in the opposite direction to the horizontal force applied to the back surface 31b of the caisson 31 due to the earthquake motion, the horizontal force applied to the back surface 31b of the caisson 31 caused by the earthquake motion can be reduced and the required weight of the caisson can be reduced.

  Moreover, the reliability of the earthquake-resistant structure which the quay structure of this embodiment has improves by monitoring the water level H on a daily basis, and draining with the drainage pump 18 based on this water level monitoring.

  As described above, according to the gravity quay structure of FIG. 4, the water pressure is applied from the sea side to the land side, thereby improving the stability of the gravity quay during an earthquake and reducing the required weight of the caisson. Can do.

  In addition, in the case of a gravitational quay as in this example, the buoyancy acting on the laying body such as caisson is reduced due to the lowering of the water level on the back surface, and the weight of the levee body is increased, so that the effect of further increasing the stability can be obtained. .

  Next, although the 2nd example by this embodiment is a gravity type quay structure, as shown in FIG. 5, a water-stop sheet pile is abbreviate | omitted so that the passage of groundwater may not arise with respect to the surrounding ground by a water-impervious sheet. The point which comprised the water-impervious part 42 differs from FIG.

  That is, the water-impervious sheet 34 of the water-impervious portion 42 extends from the back surface 31b of the caisson 31 to the bottom rubble P, the slope of the buried soil M, and further to the ground surface. It covers the soil M. One end 34b of the water shielding sheet 34 extends to the upper end of the back surface 31b of the caisson 31 and is fixed to be impermeable, and the other end 34c is fixed to the ground surface to be impermeable.

  As described above, when the water level H in the water level lowering range A rises behind the gravity-type quay by constructing a portion where the water-impervious sheet 34 of the water-impervious portion 42 prevents the passage of groundwater from the surrounding ground. By maintaining the water level H constantly below the set water level by the drainage pump 38, it is possible to construct a quay structure in which the state in which the water level is lowered lasts permanently.

  By controlling the water level H within the water level lowering range A of the water shielding portion 42 with the drainage pump 38 so as to be lower than the set water level as in FIG. 2, the water level HS at the sea level and the water level within the water level lowering range A are controlled. The water pressure due to the water level difference ΔH (HS−H) from H constantly acts on the front surface 31 a of the caisson 31.

  As described above, according to the gravitational quay structure of FIG. 5, the stability of the gravitational quay during an earthquake is improved by applying water pressure from the sea side to the land side as in FIG. Weight can be reduced.

  Further, since the water-stop sheet pile is omitted, the water-stop sheet pile material and its placement are unnecessary, which can contribute to cost reduction of materials and man-hours.

  Next, the third example according to the present embodiment is a gravitational quay structure. As shown in FIG. 6, the basic configuration is substantially the same as in FIG. The point which extended to the upper end and comprised the water shielding part 52 differs from FIG.

  That is, the water-impervious sheet 34 of the water-impervious portion 52 is formed between the front surface 31a of the caisson 31 and the bottom surface of the caisson 31, the bottom surface of the back surface 31b, the slope of the buried soil M, and the ground surface. And covers the front surface 31a of the caisson 31, the foundation rubble P, and the buried soil M. One end 34b of the water shielding sheet 34 extends to the upper end of the back surface 31b of the caisson 31 and is fixed to be impermeable, and the other end 34c is fixed to the ground surface to be impermeable.

  As described above, when the water level H in the water level lowering range A is increased behind the gravity quay by constructing a part where the groundwater does not flow to the surrounding ground by the water shielding sheet 34 of the water shielding part 52 By maintaining the water level H constantly below the set water level by the drainage pump 38, it is possible to construct a quay structure in which the state in which the water level is lowered lasts permanently.

  By controlling the water level H within the water level lowering range A of the water shielding portion 42 with the drainage pump 38 so as to be lower than the set water level as in FIG. 2, the water level HS at the sea level and the water level within the water level lowering range A are controlled. The water pressure due to the water level difference ΔH (HS−H) from H constantly acts on the front surface 31 a of the caisson 31.

  As described above, according to the gravity type quay structure of FIG. 6, the stability of the gravity type quay during an earthquake is improved by applying water pressure from the sea side to the land side as in FIG. Weight can be reduced.

  Moreover, since it was set as the structure which installs a water shielding sheet in the bottom face of the caisson 31, and the front surface 31a of the sea side, the inspection of a water shielding sheet, etc. are attained.

  Next, the example which provided the sheet | seat margin part in the water-impervious sheet in the gravity type quay of FIGS. 4-6 is demonstrated with reference to FIG. 7 is a partial view (a) showing an example in which a sheet margin portion is provided on the water-impervious sheet at the lower end of the back side of the caisson in FIG. 4 or FIG. 5 and a sheet margin portion on the water-impervious sheet at the lower end of the front side of the caisson in FIG. It is a partial view (b) showing an example provided.

  In the weight-type quay of FIG. 5, as shown in FIG. 7A, a sheet margin portion 34 d is provided on the water-impervious sheet 34 so that the water-impervious sheet 34 sag at the lower end portion of the back surface 31 b of the caisson 31.

  In addition, in the heavy weight type quay of FIG. 6, as shown in FIG. 7B, a sheet margin 34 e is provided on the water shielding sheet 34 so that the water shielding sheet 34 sags at the lower end portion of the front surface 31 a of the caisson 31.

  In the case of a gravity quay such as the caisson type, there is a concern that the caisson will move to the sea side when an earthquake occurs, and the water shielding sheet will be damaged. However, according to the configuration of FIGS. Even if the caisson 31 moves to the sea side, the water-impervious sheet 34 extends by slack in the sheet margin portion 34d at the lower end portion of the back surface 31b of the caisson 31 or the sheet margin portion 34e at the lower end portion of the front surface 31a. The water impervious sheet 34 can be prevented from being damaged, and the water impervious portions 42 and 52 can be kept water impervious.

Next, the amount of decrease in horizontal force due to a drop in water level was examined. That is, FIG. 8 shows the result of trial calculation of the rate of decrease (%) due to the water level drop of the horizontal force calculated as the combined force of earth pressure and water pressure by the Coulomb earth pressure formula. This assumes a stone with a top height of DL + 4.0m, an internal friction angle of φ = 40 °, and an earthquake with a horizontal seismic intensity of 0.2. As a comparison, when only the groundwater surface behind is replaced with lightweight embankment (γ = 12 kN / m ³ ), the horizontal force drop rate is about 87% (when the water depth is 16 m). It can be seen that the reduction effect is high, the design horizontal force of the levee body can be reduced, the dam body width of the gravity quay can be reduced, and the sheet pile length of the sheet pile quay can be reduced. As described above, when the amount of water level decrease is increased, the horizontal force decreases and the cost of the quay (revetment) can be reduced.

The calculation conditions are as follows.
・ Height DL + 4.0m
・ Upload 15kN / m ²
・ Soil condition Air weight 18 kN / m ³
Underwater weight 10 kN / m ³
Internal friction angle φ = 40 °
Wall friction angle 15 °
・ Water level condition No water level drop: DL + 0.67m (assuming residual water level when HWL: DL + 2.0m, LWL: DL + 0.0m)
When water level drops: Amount of water level drop from LWL

  As described above, the modes for carrying out the present invention have been described. However, the present invention is not limited to these, and various modifications can be made within the scope of the technical idea of the present invention. For example, although the quay structure has been described in the present embodiment, the present invention is not limited to this, and may be a shore structure.

  Moreover, in this embodiment, the water level in the impermeable part is made lower than the sea level on the front of the quay, and the water pressure on the front of the quay is increased from the sea side to the land side due to the water level difference between the water level in the impermeable part and the front of the quay However, the present invention is not necessarily limited to this. For example, by making the water level in the water shielding portion lower than the residual water level (RWL) on the land side, at least the water pressure to the back of the quay is lowered. Therefore, the horizontal force acting on the quay due to earthquake motion is reduced, and the stability of the quay during an earthquake can be maintained.

  According to the quay structure and revetment structure of the present invention, water pressure can be applied from the sea side to the land side, so that the required weight of the gravity quay and revetment and the sheet pile type can be maintained while maintaining the stability of the quay and revetment during an earthquake. The cross-sectional performance of the sheet pile used for the quay / quay can be reduced. For this reason, construction cost reduction of a quay structure and a seawall structure is attained, maintaining earthquake resistance.

DESCRIPTION OF SYMBOLS 11 Steel pipe sheet pile 12 Water shielding part 13 Rubble stone 14 Water shielding sheet 17 Water stopping sheet pile 18 Drain pump 18a Suction port 22 Water shielding part 31 Caisson 31a The front face of caisson 31b The back face of caisson 32 Water shielding part 33 Rubble stone 34 Water shielding sheet 34d, 34e Seat margin 37 Stop sheet pile 38 Drain pump 38a Suction port 42,52 Water blocking part A Water level lowering range G Water bottom H Water level within water level lowering range A HS Water level of sea level L Viscous soil layer P Basic rubble ΔH Water level difference

Claims (5)

Provide a water-blocking part on the back of the quay or revetment so as to block the groundwater from entering and leaving the surrounding ground,
The water-impervious portion has a sheet material laid so as to cover the ground in order to block the entry and exit of the groundwater, and a water-permeable material deposited on the sheet material,
The drainage means is installed in the impermeable part , and the quay or the revetment has earthquake resistance by keeping the water level in the impermeable part lower than the water level of the sea surface in front of the quay or revetment by the drainage means. Wharf structure or revetment structure. The quay structure or revetment structure according to claim 1 , wherein the water shielding portion has a water stop sheet pile, and the water stop sheet pile is disposed a predetermined distance away from the back surface of the quay wall or revetment. When the quay or revetment is a caisson gravity type, the sheet material is laid to the upper end of the back or front of the caisson, and a sheet margin is provided so that the sheet material sag at the lower end of the back or front. The quay structure or revetment structure according to 1 or 2 . The quay structure or revetment structure according to claim 1 or 2 , wherein an impermeable portion of the original ground is used instead of the sheet material. The drainage means comprises a drainage pump;
A water level meter is installed in the water shielding part,
The quay according to any one of claims 1 to 4, wherein when the water level gauge detects that the water level in the impermeable portion has reached a set water level, the drain pump is automatically driven based on the detection. Structure or revetment structure.

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