JP4900236B2 - Shear transmission structure, concrete structure, construction method of shear transmission structure, and design method of shear transmission structure - Google Patents

Description

  The present invention relates to a shear transmission structure for transmitting a shear force acting between an underground wall and a concrete structure constructed by joining the underground wall, a concrete structure including the same, and the construction of the shear transmission structure The present invention relates to a method and a design method of the shear transmission structure.

  Conventionally, in order to prevent the tank from rising due to earth pressure or water pressure acting on the bottom surface of the LNG underground tank, the joint reinforcement between the joint surface between the underground wall constructed on the outer periphery of the LNG underground tank and the side wall of the tank Or by constructing a structure that transmits a shearing force as described in Patent Document 1 or 2, for example, the lift load of the tank is transmitted to the underground wall, and due to its own weight and pulling resistance Techniques for resisting have been proposed.

Specifically, Patent Document 1 discloses a shear transmission in which a protruding portion that protrudes inwardly at the top of a continuous underground wall and a stepped portion that engages with the protruding portion on a side wall of the underground tank. A structure is disclosed. Patent Document 2 discloses a shear transmission structure having a shape in which an underground continuous wall forming the outer periphery of an underground tank expands in the depth direction.
JP 2003-41608 A Japanese Patent Laid-Open No. 7-229321

  However, when jointed reinforcing bars are provided, not only does the material cost of the reinforcing bars increase, but there is a risk that the concrete will be insufficiently filled during construction of underground walls and concrete structures. In addition, it takes time for construction.

  Moreover, since the structure of the shear transmission structure disclosed in Patent Documents 1 and 2 is complicated, there is also a problem that it takes time for construction, and high technology is required for construction.

  The present invention has been made in view of the above points, and can transmit a shear force between an underground wall and a concrete structure constructed by joining the underground wall with a simple configuration. The purpose is to do.

In order to achieve the above object, the present invention is a shear transmission structure that transmits a shear force acting between an underground wall and a concrete structure constructed by joining the underground wall,
The joining surfaces of the concrete structure and the underground wall is wavy to engage each other, sawtooth, or have a concave-convex shape of the substantially trapezoidal shape,
When the concrete structure moves relative to the underground wall in the vertical direction, the joint surfaces move relative to each other in the vertical direction, and the top of one convex portion of the joint surfaces is the top of the other convex portion. On the basis of the load acting on the concrete structure and the underground wall according to the separation of the joint surface and the coefficient of friction between the joint surfaces. frictional force obtained Te, characterized in Rukoto Do greater than the vertical direction of the load acting on the concrete structure (first invention).

  According to the shear transmission structure of the present invention, it can be easily constructed without requiring labor and advanced techniques for construction, such as the jointed reinforcing bar and the shear transmission structure described in Patent Documents 1 and 2, and can be applied to a concrete structure. It is possible to transmit a vertical load such as a lifting load acting on the underground wall.

In addition , for example, when a vertical load acts on a concrete structure and moves slightly, both joint surfaces of the concrete structure and the underground wall are separated from each other. A reaction force is generated to return the separation to the state before separation, and the frictional force between the joint surfaces (= shear transmission resistance) increases in accordance with this reaction force, so the load in the vertical direction is effective between both joint surfaces. Can be communicated to.

In addition , an uneven shape that reliably transmits the load from the concrete structure to the underground wall without slipping the joint surface between the concrete structure and the underground wall with respect to the vertical load acting on the concrete structure, It can be formed efficiently in construction.

The second invention is a concrete structure constructed by joining with an underground wall having an uneven shape on the surface,
Wherein the joint surface to be bonded to the ground wall, the underground wall of irregular shape and meshes such wavy, serrated, or have a concave-convex shape of the substantially trapezoidal shape,
When the concrete structure moves relative to the underground wall in the vertical direction, the joint surfaces move relative to each other in the vertical direction, and the top of one convex portion of the joint surfaces is the top of the other convex portion. On the basis of the load acting on the concrete structure and the underground wall according to the separation of the joint surface and the coefficient of friction between the joint surfaces. frictional force obtained Te, characterized in Rukoto Do greater than the vertical direction of the load acting on the concrete structure.

3rd invention is applied to the LNG underground tank in 2nd invention, It is characterized by the above-mentioned.

4th invention is the construction method of the shear transmission structure which transmits the shear force which acts between the underground wall and the concrete structure constructed by joining with the underground wall,
Corrugated on its surface, sawtooth, or have a concave-convex shape of the substantially trapezoidal, when the concrete structure is relatively moved in a vertical direction with respect to the diaphragm wall, wherein the joining faces are relatively moved in the vertical direction Then, when the top of one convex portion of both joint surfaces rides on the top of the other convex portion, the two joint surfaces are separated from each other, and the concrete structure and the ground according to the separation of the joint surfaces. a load acting on the middle wall, the friction coefficient and frictional force determined on the basis of the between both joint surfaces, to construct a diaphragm wall ing larger than the load in the vertical direction acting on the concrete structure,
Place concrete so that it touches the uneven surface of the underground wall,
The placed concrete is cured.

A fifth aspect of the invention is a design method for a shear transmission structure according to the first aspect of the invention, in which the frictional forces of the joint surfaces are moved relative to each other in the vertical direction so that the joint surfaces When the top of one convex part rides on the top of the other convex part, the load acting on the concrete structure and the underground wall according to the separation of the joint surface, and the friction between the joint surfaces It is calculated | required based on a coefficient, and the uneven | corrugated shape of the said both joint surfaces is set so that the said friction force may become larger than the load of the perpendicular direction which acts on the said concrete structure.

  According to the present invention, it is possible to transmit a shear force between an underground wall and a concrete structure constructed by joining the underground wall with a simple configuration.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view of an LNG underground tank 10 according to the present embodiment.
As shown in FIG. 1, the LNG underground tank 10 is constructed in the ground 40 and has an underground continuous wall 20 (hereinafter referred to as a continuous wall 20) that functions as a temporary earth retaining wall or a water blocking wall, and a continuous wall 20. It has a double cylindrical shell structure composed of a storage tank main body 30 constructed by being joined to each other.

FIG. 2 is an enlarged cross-sectional view of the joint surface between the continuous wall 20 of FIG. 1 and the side wall 32 of the storage tank body 30.
As shown in FIG. 2, the shear wall 20 and the tank body are constructed as a shear transmission structure 1 that transmits a shearing force (= that is, a load acting in the vertical direction) acting between the wall 20 and the side wall 32 of the tank body 30. Both joint surfaces with the side wall 32 of 30 have the uneven | corrugated shape which meshes | engages mutually. Thereby, for example, when a floating load or the like acts on the storage tank body 30 and the side wall 32 moves in the shearing direction with respect to the continuous wall 20 (that is, relative movement in the vertical direction), the two joint surfaces are separated from each other. Will move. When the two joint surfaces are separated from each other, the side wall 32 and the connecting wall 20 have a cylindrical structure. Therefore, the side wall 32 is subjected to a compressive axial load that reduces the diameter. An axial load in the tension direction that expands the diameter acts, and the ground 40 is pressed from the contact surface of the continuous wall 20 as the diameter of the continuous wall 20 increases, and a compressive load acts on the ground 40. A reaction force that tries to return the load separation to the state before separation occurs, and the friction force between the joint surfaces (= shear transmission resistance) increases according to this reaction force, so that the shear force is ensured between both joint surfaces. To be communicated to.
The LNG underground tank 10 having such a shear transmission structure 1 is constructed as follows.

FIG. 3 is a process diagram showing a construction procedure of the LNG underground tank 10 having the shear transmission structure 1.
As shown in FIG. 3, the construction procedure of the LNG underground tank 10 includes a continuous wall construction step S <b> 1 for constructing the continuous wall 20 in which the roughening 35 is formed, and the side wall 32 of the storage tank body 30 is the roughening 35 of the continuous wall 20. A storage tank body concrete placing step S2 for placing the concrete 38 of the storage tank body 30 and a concrete curing step S3 for curing the placed concrete 38 so as to be joined to the surface of the storage tank.

  In the continuous wall construction step S <b> 1, first, the continuous wall 20 is constructed on the ground 40. Construction of the continuous wall 20 can be performed using a general known construction method. Then, after the continuous wall 20 is sufficiently cured and hardened, a chipping process is performed on the surface inside the continuous wall 20 (the side on which the storage tank body 30 is constructed) to form the roughening 35. The chipping process can be easily performed by using, for example, a spiky hammer sold by CAE Co., Ltd. as a rock drilling attachment on a construction machine. Here, when performing the chipping process, the unevenness of the roughening 35 is formed to have a predetermined height difference. The detailed design of the uneven height difference will be described later.

  In the storage tank body concrete placing step S2, the concrete 38 serving as the side wall 32 of the storage tank body 30 is placed so as to be in contact with the roughening 35 on the surface of the continuous wall 20 constructed in the continuous wall construction step S1.

  In the concrete curing process S3, the concrete 38 constituting the side wall 32 of the storage tank body 30 cast in the storage tank body concrete placing process S2 is sufficiently cured and cured.

  By performing these steps S <b> 1 to S <b> 3, the continuous wall 20 in which the roughening 35 is formed becomes a mold, and the concrete 38 on the side wall 32 of the storage tank body 30 is placed and cured, and the continuous wall 20 and the side wall 32 are Thus, wavy irregularities that engage with each other are constructed.

  However, actually, even if a shearing force does not act between the continuous wall 20 and the side wall 32 due to the water pressure of groundwater entering between the continuous wall 20 and the side wall 32, the continuous wall 20 and the side wall 32 A gap is formed between the two. This will be specifically described together with the design of the height difference of the unevenness described later.

Next, the lifting force acting on the storage tank body 30 will be described using specific numerical values.
FIG. 4 is an explanatory diagram for obtaining a vertical load (hereinafter referred to as an applied load W) acting between the side wall 32 and the continuous wall 20 when the maximum lifting force is applied to the LNG underground tank 10. FIG. 5 is a cross-sectional view showing specific dimensions of the LNG underground tank 10. It is assumed that no LNG is stored in the LNG underground tank 10.

Working load W is the reservoir body weight W _tu shown in FIG. 4, uplift W _U, and is obtained by the following expression (1) using the increased load W _e during an earthquake.
W = -W _tu + W _U + W _e (1)
The storage tank body weight W _tu is obtained, for example, from the sum of the side wall weight W _t1 of the side wall 32, the bottom plate weight W _t2 of the bottom plate 36, and the incidental weight W _t3 of the roof portion or the like as in the following equation (2). .
W _tu = W _t1 + W _t2 + W _t3 (2)
Further, the side wall weight W _t1 is increased in thickness as the weight W _s1 of the general portion 33 having a constant thickness of the side wall 32 and the thickness of the lower portion of the side wall 32 shift downward as shown in the following equation (3). determined by the sum of the weight W _s2 of comprising the side wall lower end haunch portions 34.
W _t1 = W _s1 + W _s2 (3)
For example, in the case of the dimensions of the storage tank body 30 as shown in FIG. 5, if the unit volume weight of the concrete is 24.0 kN / m ³ , the weight W _s1 of the general part 33 is
W _s1 = (38.414 ² -36.014 ² ) × π × (15.800 + 25.158) × 24.0 + π × 1.20
× {38.414 ^2- (36.014 ² + 36.014 × 37.214 + 37.214 ² ) / 3} × 24.0
= 563.84 × 10 ³ kN (4)
The weight W _s2 of the side wall lower end haunch part 34 is
W _s2 = π × 3.00 × {36.014 ^2- (33.014 ² + 33.014 × 36.014 + 36.014 ² ) / 3} × 24.0
= 23.76 × 10 ³ kN ・ ・ （5）
Therefore, the side wall weight W _t1 is
W _t1 = 563.84 × 10 ³ + 23.76 × 10 ³ = 587.60 × 10 ³ kN ・ ・ （6）
It becomes.

The bottom plate weight W _t2 is
W _t2 = 38.414 ² × π × 6.4 × 24.0 = 712.07 × 10 ³ kN (7)
It becomes.

Further, the incidental weight W _t3 is the weight of the incidental member 37 such as a temporary steel roof, a suspended deck, a ring plate, a barrel / nozzle, a stage, an internal scaffold, a membrane, a cold insulation panel, and the LNG underground tank 10 shown in FIG. In the case of, it will be around 1698ton, so multiply by the gravitational acceleration,
W _t3 = 1698ton × 9.80665 = 16.65 × 10 ³ kN ・ ・ （8）
It becomes.
Therefore, W _tu is the sum of W _t1 , W _t2 , W _t3 ,
W _tu = 587.60 × 10 ³ + 712.07 × 10 ³ + 16.65 × 10 ³ = 1316.32 × 10 ³ kN ・ ・ （9）
It becomes.

As the lifting pressure W _U , for example, the buoyancy acting under the bottom slab 36 at the time of high groundwater level in the ground 40 (groundwater level DL + 3.300 m) is obtained. The lifting pressure W _U is obtained by the following equation (10),
W _U = ρ _w × g × π × r ² × h (10)
Specifically, if the dimensions of FIG. 5 are substituted,
W _U = 1.00 × 9.80665 × π × 38.414 ² × (3.3 + 31.558) = 1584.72 × 10 ³ kN
It becomes. Here, [rho _w is the density of water, g is the gravitational acceleration, the distance r from the tank center to the outer surface of the side wall 32, h is the depth from the groundwater level to the bottom plate 36 the lower end.

When increased load W _e earthquake, a inertial force acting in a vertical upward direction during an earthquake, the following equation (11), each portion of the LNG underground tanks 10 (side wall 32, bottom plate 36, bearing member 37) The vertical design seismic intensity (K _V1-3 ) set by, is obtained by adding the product of the weight of each part (side wall weight W _t1 , bottom plate weight W _t2 , incidental weight W _t3 ),
W _e = K _V1 × W _t1 + K _V2 × W _t2 + K _V3 × W _t3 (11)
Specifically, in the case of the LNG underground tank 10 shown in FIG.
W _e = 0.119 × 587.60 × 10 ³ + 0.082 × 712.07 × 10 ³ + 0.150 × 16.65 × 10 ³ = 130.81 × 10 ³ kN
It becomes.

As described above, the applied load W is calculated as follows using the formula (1), with the upward direction being positive.
W = -W _tu + W _U + W _e (1)
= −1316.32 × 10 ³ + 1584.72 × 10 ³ + 130.81 × 10 ³ = 399.21 × 10 ³ kN
Therefore, the design shear force W _d is taken into account when the load factor is 1.1.
W _d = 1.1 × W = 439.13 × 10 ³ kN ・ ・ （12）
It becomes.
This as opposed to the design shear force W _d obtained by the frictional force the joining surface between the continuous wall 20 and side walls 32 (= shear transfer strength) is obtained as follows.

As shown in FIG. 2, as the floating load S acts on the storage tank body 30 and the side wall 32 moves in the shearing direction (that is, relative movement in the vertical direction) with respect to the continuous wall 20, both joint surfaces become Let δ be a distance away from each other (hereinafter referred to as a distance). When the compressive force generated on the side wall 32, the continuous wall 20, and the ground 40 according to the separation amount δ is σ _nd , the shear transmission resistance Vcwd is expressed by the following equation (13) with respect to the compressive force σ _nd . It is calculated as the reaction force -σ _nd multiplied by the friction coefficient μ.
Vcwd = μ × (-σ _nd ) (13)
FIG. 6 is a cross-sectional view of the LNG underground tank model in which the side wall 32 and the connecting wall 20 of the LNG underground tank 10 are represented as a double ring.

As shown in FIG. 6, the radius of R from the center of the double ring to the boundary between the side walls 32 and Renkabe 20, P _W is the internal pressure acting on the side wall 32 side from the boundary, P _S is continuous wall from the boundary 20 The external pressure acting on the side, E _{c, w} is the Young's modulus of the side wall 32, E _{c, w} is the Young's modulus of the continuous wall 20, tw is the side wall thickness, and ts is the continuous wall thickness. In addition, assuming that the ground 40 on which the continuous wall 20 is constructed is a spring, it is a kg spring coefficient.

Here, the distance δ between the side wall 32 and the continuous wall 20 is determined by the amount of displacement δ _w of the side wall 32 to the inside of the storage tank body 30 and the amount of displacement δ to the outside of the continuous wall 20 as shown in the following equation (14). It is calculated as the sum of _s .
δ = δ _w + δ _s (14)
Here, when the ring is displaced inward by δ _w , the internal pressure P _W acts on the side wall 32. At this time, the axial force _{Nθ, w} acting in the circumferential direction of the side wall 32 is expressed by the following equation (15).
N _{θ, w} = P _{W ・} R _W・ ・ （15）
R _w is the radius of the side wall 32.

式（１５）及び式（１６）は、次式（１８）のように整理される。

一方、円環がδ_sだけ外側へ変位するためには、連壁２０には、外圧P_Sから地盤４０からの反力kgδ_sを差引いた力（P_S-kgδ_s）が作用するので、式（１５）〜（１８）と同様に、連壁円周方向に作用する軸力N_θ,sは、次式（１９）のように表される。

ここで、P_wとP_sとは作用・反作用の関係にあるのでP_w=P_sであり、またR_w≒R_s=Rとすると、式（１８）と式（１９）は次式（２０）のように整理される。

また、式（２０）からP_w・Rを消去して整理すると、δ_wは次式（２１）のように表される。

ここで、具体的に図５のＬＮＧ地下タンク１０のケースをあてはめ、DL-12.772m以浅又は以深によってヤング率がE_1c,w又はE_2c,wに変化すると仮定すると、これらの深度域に対応する側壁３２の内側への変位量δ_w1又はδ_w2は、次式（２２）及び（２３）のように計算される。

ただし、上記計算には、E_1c,w＝28kN/mm²(DL-12.772m以浅)、E_2c,w＝31kN/mm²(DL-12.772m以深)、t_w＝2400mm、E_c,s＝33kN/mm²、t_s＝1000mm、K_g =0.0050N/mm²、R=38414mmを用いた。 Here, N _{θ, w} is also expressed by the following equation (16) using the side wall circumferential strain ε _{θ, w} :
N _{θ, w} = ε _{θ, w} × E _{c, w} × t _w (16)
Since the side wall circumferential strain ε _{θ, w} is expressed by the following equation (17),

Expressions (15) and (16) are arranged as the following expression (18).

On the other hand, in order for the ring to be displaced outward by δ _s, a force (P _S -kg δ _s ) obtained by subtracting the reaction force kg δ _s from the ground 40 from the external pressure P _S acts on the connecting wall 20. Similar to the equations (15) to (18), the axial force _{Nθ, s} acting in the circumferential direction of the connecting wall is expressed as the following equation (19).

Here, since P _w and P _s are in a relationship of action and reaction, P _w = P _s and when R _w ≈R _s = R, Equation (18) and Equation (19) are expressed by the following equation ( 20).

Further, when P _w · R is deleted from the equation (20) and rearranged, δ _w is expressed as the following equation (21).

Here, the case of the LNG underground tank 10 of FIG. 5 is specifically applied, and assuming that Young's modulus changes to E _{1c, w} or E _{2c, w} by DL-12.772m shallower or deeper, it corresponds to these depth regions. The amount of displacement δ _w1 or δ _w2 to the inside of the side wall 32 is calculated as in the following equations (22) and (23).

However, the above _{calculation, E 1c, w = 28kN /} mm 2 (DL-12.772m _{shallower), E 2c, w = 31kN} / mm 2 (DL-12.772m _{deeper), t w = 2400mm, E} c, s = 33 kN / mm ² , t _s = 1000 mm, K _g = 0.0050 N / mm ² , R = 38414 mm were used.

したがって、式（２２）及び式（２３）を式（２４）及び式（２５）に代入することにより、内圧P_w1及びP_w2、外圧P_s1及びP_s2は、次式（２６）及び（２７）のように整理される。
P_w1=P_s1=0.045×0.375δ=0.017δ (DL-12.772以浅) ・・（２６）
P_w2=P_s2=0.050×0.352δ=0.018δ (DL-12.772以深) ・・（２７）
一方、図３で説明したように、ＬＮＧ地下タンク１０構築後に、側壁３２と連壁２０との間にせん断力が作用しない場合でも、連壁２０と側壁３２との間には隙間が生じる。これは、貯槽本体３０内のＬＮＧからの冷熱によって側壁３２及び連壁２０が収縮したり、貯槽本体３０及び連壁２０に地下水圧の作用したりすることによる。 Further, the internal pressures P _w1 and P _w2 acting on the side wall 32 side from the boundary due to the depth are obtained from the equation (20) as the following equations (24) and (25).

Therefore, by substituting the equations (22) and (23) into the equations (24) and (25), the internal pressures P _w1 and P _w2 and the external pressures P _s1 and P _s2 are _expressed by the following equations (26) and (27 ).
P _w1 = P _s1 = 0.045 × 0.375δ = 0.017δ (DL-12.772 or less) ・ ・ （26）
P _w2 = P _s2 = 0.050 × 0.352δ = 0.018δ (DL-12.772 or deeper) (27)
On the other hand, as described with reference to FIG. 3, after the LNG underground tank 10 is constructed, a gap is generated between the continuous wall 20 and the side wall 32 even when a shearing force does not act between the side wall 32 and the continuous wall 20. This is because the side wall 32 and the continuous wall 20 contract due to cold heat from the LNG in the storage tank body 30, or the ground water pressure acts on the storage tank body 30 and the connection wall 20.

FIG. 7 is a graph showing the displacement of the side wall 32 and the continuous wall 20 due to cold from LNG.
The displacement of the side wall 32 shown in FIG. 7 is calculated | required with the temperature load obtained from the structural analysis of a housing. In addition, the displacement of the continuous wall 20 includes the average temperature T = -12.29 ° C. of the continuous wall 20 obtained by the temperature analysis of the frame, the initial temperature To = 16.6 ° C. of the ground 40, and the linear expansion coefficient α of the concrete = 1.0 × 10 − 5. The displacement δ is calculated by the following equation (28) assuming that the radius R of the continuous wall 20 is 38414 mm.
δ = R × α × (T−T ₀ ) = 38414 × 1.0 × 10 ⁻⁵ × (−12.29−16.6) = − 11.1 mm (28)
FIG. 8 is a graph showing displacement of the side wall 32 due to water pressure and lift pressure.
The displacement of the side wall 32 shown in FIG. 8 is calculated | required by the water pressure and lifting pressure obtained from the structural analysis of a housing.

FIG. 9 is a graph showing the displacement of the continuous wall 20 due to water pressure.
As shown in FIG. 9, the connecting wall 20 is displaced outward by the pressure of water that enters between the side wall 32 and the connecting wall 20. This is based on the equations (22) and (23) and the equations (26) and (27), as shown in the following equations (29) and (30). The displacements δ _s1 and δ _{s2 of the connecting} wall 20 due to _s1 and P _s2 are obtained.
δ _s1 = (1-0.375) δ = 0.625 δ = 0.625 / 0.017 x P _s1 (DL-12.772 or less) (29)
δ _s2 = (1-0.352) δ = 0.648 δ = 0.648 / 0.018 x P _s2 (DL-12.72 or deeper) (30)
FIG. 10 is a graph showing the total displacement amount due to the temperature, the hydraulic pressure, and the lifting pressure for the side wall 32 and the continuous wall 20, and FIG. 11 shows the displacement difference between the side wall 32 and the continuous wall 20 of FIG. It is a graph to show.
As shown in FIGS. 10 and 11, the difference in displacement between the side wall 32 and the continuous wall 20, that is, the gap (2 to 14 mm) increases as it moves downward, and its average is 10.8 mm.

  That is, when the gaps as described above are generated, the meshing between the side wall 32 and the continuous wall 20 is initially 15 mm even if the roughening 35 having a difference in height of 15 mm is formed on the surface of the continuous wall 20 by chipping. The average is about 4.2mm (= 15mm-10.8mm).

  Therefore, the shear transmission resistance when the meshing is 4.2 mm is obtained. That is, the joint surfaces of the side wall 32 and the continuous wall 20 are moved relative to each other in the vertical direction, and the top of one convex portion of both joint surfaces rides on the top of the other convex portion, thereby separating the joint surfaces. Find the frictional force generated between the two contact surfaces when the value becomes 4.2 mm (when the meshing becomes zero).

When the meshing is 4.2 mm, the internal pressure P _w and the external pressure P _s required for the side wall 32 and the continuous wall 20 to overcome the unevenness formed on both joint surfaces are set as follows: And substituting into equation (27),
P _w1 ＝ P _s1 ＝ 0.0714 N / mm ²・ ・ （31）
P _w2 = P _s2 = 0.0756 N / mm ² (32)
It becomes.

However, σ _nd = -σ _nd / 2 is used in consideration of the fact that σ _nd is compressed in accordance with “Concrete Standard Specification 6.3.7 Design Shear Transmission Force”. Therefore, it is assumed that the compressive force of the following equations (33) and (34) is handled in the equation of the shear transfer resistance Vcwd as the average stress acting perpendicularly to the shear plane.
_{―Σ nd1} ＝ P _w1 / 2 ＝ P _s1 /2＝0.0357N/mm ²・ ・ （33）
_{―Σ nd1} ＝ P _w2 / 2 ＝ P _s2 /2＝0.0378N/mm ²・ ・ （34）
The basic formula of the shear transmission strength Vcwd is expressed as the following formula (35).
Vcwd = | (τ _c + p, τ _s , sin ² θ−α, p, fyd, sin θ, cos θ), Ac + Vk | / γ _b (35)
However, in this embodiment, since there is no reinforcing bar on the shear plane between the side wall 32 and the continuous wall 20 and there is no shear key, the expression (35) is arranged as the following expression (36). .
Vcwd = τ _c · Ac / γ _b , where τ _c = μ · f′cd ^b (−σ _nd ) ^1−b ·· (36)
Here, μ is an average friction coefficient regarding solid contact, Ac is an area of a shear plane, γ _b is a member coefficient, and b is a coefficient representing a surface shape.

Specifically, substituting the specific dimensions of the LNG underground tank 10 shown in FIG.
h1: Side wall height (DL + 4.000 to −12.772m): 16.772m (37)
h2: Side wall height (DL-12.72 to -28.358m): 15.586m (38)
Ac1 = 2 × R × π × h1 = 2 × 38.414 × π × 16.772 = 4048m ² (39)
Ac2 = 2 × R × π × h2 = 2 × 38.414 × π × 15.586 = 3761m ² (40)
γ _b = 1.3 (41)
f'cd = f'ck / γ _c = 30 / 1.3 = 23.1N / mm ² (DL-12.772m or less) ・ ・ （42）
f'cd = f'ck / γ _c = 40 / 1.3 = 30.8N / mm ² (DL-12.772m or deeper) (43)
σ _nd : Average stress acting perpendicularly to the shear plane (44)
Shear transmission force Vcwd is
Vcwd1 ＝ τ _c・ Ac1 / γ _b ＝ 0.45 × (23.1) ^1/2 × (0.0357) ^1/2 × 4048 × 10 ⁶ /1.3≒1,272,000kN ・ ・ （45）
Vcwd2 ＝ τ _c・ Ac2 / γ _b ＝ 0.45 × (30.8) ^1/2 × (0.0378) ^1/2 × 3761 × 10 ⁶ /1.3≒1,405,000kN ・ ・ （46）
By
Vcwd = Vcwd1 + Vcwd2 = 1272000 + 1405000 = 2677000kN (47)
Is calculated.

That is, this shear transmission force Vcwd (2677000 kN) is designed when the shear force is the largest between the side wall 32 of the storage body 30 of the LNG underground tank 10 and the continuous wall 20 obtained by the equation (12). It is sufficiently larger than the shearing force W _d (439.13 × 10 ³ kN). As a result, even though the initial engagement of the side wall 32 and the continuous wall 20 is 15 mm, even when the average is about 4.2 mm (= 15 mm-10.6 mm), the joint surface between the side wall 32 and the continuous wall 20 The shear force can be transmitted without overcoming the irregularities formed on the surfaces of each other.

In the present embodiment, as described above, the level difference of the roughening 35 formed on the surface of the continuous wall 20 is set first, and both the gaps formed between the continuous wall 20 and the side wall 32 are determined based on the height difference. Although the substantial meshing amount between the contact surfaces was obtained, and the shear transmission force Vcwd based on the meshing amount was obtained, it was evaluated whether the height difference was appropriate for transmitting the shearing force. , not limited thereto, together with on the basis of the design shear force W _d envisioned, it shear transfer force Vcwd calculates necessary to set the amount engagement based on the shear transmission force Vcwd, continuous wall 20 and the side wall The height difference of the roughening 35 may be obtained by taking into account the gap generated between the two.

Specifically, the steps up to obtaining the internal pressures P _W1 and P _W2 and the external pressures P _s1 and P _{s2 up} to the expressions (26) and (27) are as described above.

Here, when calculating the level difference of the roughening 35, σ _nd = -σ _{nd in} consideration of the fact that σ _nd is a compression side according to “Standard Specification for Concrete 6.3.7 Design Shear Transmission Strength”. Using / 2, equations (26) and (27) are transformed into the following equations (48) and (49).
_{−σ nd1} = −0.0085δ N / mm ² (48)
_{−σ nd2} = −0.0090δ N / mm ² (49)
By treating these equations as −σ _nd in equation (36) and substituting the specific dimensions used in equations (37) to (44), the shear transmission force Vcwd is
Vcwd1 ＝ τ _c・ Ac1 / γ _b
＝ 0.45 × (23.1) ^1/2 × (0.0085δ) ^1/2 × 4048 × 10 ⁶ /1.3≒620900×δ ^1/2 kN ・ ・ （50）
Vcwd2 ＝ τ _c・ Ac2 / γ _b
＝ 0.45 × (30.8) ^1/2 × (0.0090δ) ^1/2 × 3761 × 10 ⁶ /1.3≒685400×δ ^1/2 kN ・ ・ （51）
By
Vcwd = Vcwd1 + Vcwd2
＝ 620900 × δ ^1/2 ＋ 685400 × δ ^1/2 ＝ 1306000 × δ ^1/2 kN ・ ・ （52）
Is calculated.

Then, based on the design shear force W _d (439.13 × 10 ³ kN) obtained when the shear force is the largest acting on the continuous wall 20 from the side wall 32 of the storage body 30 of the LNG underground tank 10 previously obtained, The amount of meshing required for the above is obtained as in the following equation (53).
1306000 × δ ^1/2 ≧ 439 130
δ ≧ 0.113mm ・ ・ (53)
As described above, the distance between the side wall 32 and the continuous wall 20 increases as it moves below the joint surface, and is 2 mm to 14 mm. Therefore, the height difference of the joint surface between the side wall 32 and the continuous wall 20 formed at the time of construction is calculated as shown in the following equation (54) on the assumption that a maximum distance of 14 mm is generated.
δ ₀ = 0.113 + 14.0 ≒ 15.0 (mm) (54)
As mentioned above, according to the shear transmission structure 1 of the LNG underground tank 10 which concerns on this embodiment, the floating load which acts on the storage tank main body 30 by continuous wall construction process S1, storage tank main body concrete placement process S2, and concrete curing process S3. It is possible to easily construct a structure capable of transmitting a vertical load such as the like to the continuous wall 20.

  In addition, since both joint surfaces of the continuous wall 20 and the side wall 32 of the storage tank body 30 have an uneven shape that meshes with each other, for example, a floating load acts on the storage tank body 30 and the side wall 32 is connected. When moving in the shearing direction with respect to the wall 20 (that is, relative movement in the vertical direction), both joint surfaces move so as to be separated from each other. And if both joint surfaces leave | separate, a load will act on the side wall 32, the continuous wall 20, and the ground 40, The reaction force which tries to return separation with respect to these loads to the state before separation arises, and this reaction force Accordingly, the frictional force between the joint surfaces (= shear transmission resistance) also increases, so that the shear force can be reliably transmitted between the joint surfaces.

  In addition, the concave and convex shapes of both joint surfaces are such that the joint surfaces are separated by the relative movement of both joint surfaces in the vertical direction and the top of one convex portion of both joint surfaces riding on the top of the other convex portion. The frictional force (= shear transmission resistance Vcwd) determined based on the load acting on the side wall 32, the connecting wall 20 and the ground 40 in accordance with the friction coefficient μ between the joint surfaces acts on the side wall 32. By being formed so as to be larger than the vertical load S to be applied, the load is stored in the storage tank without slipping of the joint surface between the side wall 32 and the connecting wall 20 with respect to the vertical load acting on the side wall 32. An uneven shape that is reliably transmitted from the main body 30 to the continuous wall 20 can be efficiently formed in terms of construction.

  In addition, although both the joint surfaces of the storage tank main body 30 and the continuous wall 20 of this embodiment were formed in the waveform, it is not restricted to this, A sawtooth shape or a substantially trapezoid shape may be sufficient. That is, the uneven shape of both joint surfaces may be a shape that allows the joint surfaces to be spaced apart when the side wall 32 moves minutely in the shearing direction with respect to the continuous wall 20.

It is a longitudinal cross-sectional view of the LNG underground tank which concerns on this embodiment. It is an expanded sectional view of the joint surface of the continuous wall of FIG. 1 and the side wall of a storage tank main body. FIG. 4 is a process diagram showing a construction procedure of the LNG underground tank 10. FIG. 5 is an explanatory diagram for obtaining a vertical load acting between the side wall 32 and the continuous wall 20 when the maximum lifting force acts on the LNG underground tank 10. FIG. 3 is a cross-sectional view showing specific dimensions of the LNG underground tank 10. It is a cross-sectional view of the LNG underground tank model in which the side wall and the continuous wall of the LNG underground tank 10 are represented as a double ring. It is a graph which shows the displacement of the side wall by the cold from LNG, and a continuous wall. It is a graph which shows the displacement of the side wall by water pressure and lifting pressure. It is a graph which shows the displacement of the continuous wall by water pressure. It is the graph which showed the total displacement amount by these temperature, water pressure, and lifting pressure about a side wall and a continuous wall. It is a graph which shows the displacement difference of the side wall and continuous wall of FIG.

Explanation of symbols

10 LNG underground tank 20 Underground continuous wall (continuous wall)
DESCRIPTION OF SYMBOLS 30 Storage tank main body 32 Side wall 33 General part 34 Side wall lower end haunch part 35 Roughening 36 Bottom plate 37 Attached member 38 Concrete 40 Ground S1 Continuous wall construction process S2 Storage tank body concrete placing process S3 Concrete curing process

Claims (5)

A shear transmission structure for transmitting a shear force acting between the underground wall and a concrete structure constructed by joining the underground wall,
The joining surfaces of the concrete structure and the underground wall is wavy to engage each other, sawtooth, or have a concave-convex shape of the substantially trapezoidal shape,
When the concrete structure moves relative to the underground wall in the vertical direction, the joint surfaces move relative to each other in the vertical direction, and the top of one convex portion of the joint surfaces is the top of the other convex portion. On the basis of the load acting on the concrete structure and the underground wall according to the separation of the joint surface and the coefficient of friction between the joint surfaces. frictional force obtained Te is, shear transfer structures characterized by Rukoto Do greater than the vertical direction of the load acting on the concrete structure. A concrete structure constructed by joining with an underground wall having an uneven shape on the surface,
Wherein the joint surface to be bonded to the ground wall, the underground wall of irregular shape and meshes such wavy, serrated, or have a concave-convex shape of the substantially trapezoidal shape,
When the concrete structure moves relative to the underground wall in the vertical direction, the joint surfaces move relative to each other in the vertical direction, and the top of one convex portion of the joint surfaces is the top of the other convex portion. On the basis of the load acting on the concrete structure and the underground wall according to the separation of the joint surface and the coefficient of friction between the joint surfaces. frictional force obtained Te is, concrete structure, characterized in Rukoto Do greater than the vertical direction of the load acting on the concrete structure.   The concrete structure according to claim 2, which is applied to an LNG underground tank. A construction method of a shear transmission structure for transmitting a shearing force acting between an underground wall and a concrete structure constructed by joining the underground wall,
Corrugated on its surface, sawtooth, or have a concave-convex shape of the substantially trapezoidal, when the concrete structure is relatively moved in a vertical direction with respect to the diaphragm wall, wherein the joining faces are relatively moved in the vertical direction Then, when the top of one convex portion of both joint surfaces rides on the top of the other convex portion, the two joint surfaces are separated from each other, and the concrete structure and the ground according to the separation of the joint surfaces. and the load acting on the middle wall, the friction coefficient and frictional force determined on the basis of the between both joint surfaces, to construct a diaphragm wall ing larger than the load in the vertical direction acting on the concrete structure,
Place concrete so that it touches the uneven surface of the underground wall,
A method for constructing a shear transmission structure between an underground wall and a concrete structure, wherein the placed concrete is cured. A method for designing a shear transmission structure according to claim 1 ,
The joint surfaces are separated by causing the frictional forces of the joint surfaces to move relative to each other in the vertical direction so that the top of one convex portion of the joint surfaces rides on the top of the other convex portion. Obtained based on the load acting on the concrete structure and the underground wall according to the friction coefficient between the joint surfaces,
A method for designing a shear transmission structure, wherein the concave and convex shapes of the joint surfaces are set such that the frictional force is greater than a vertical load acting on the concrete structure.

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