A concrete sandwich shell structure and its design and preparation method

Abstract

The present invention provides a concrete sandwich shell structure and a design and preparation method thereof. The above-mentioned concrete sandwich shell structure includes: an outer concrete shell, a functional sandwich layer and an inner concrete shell; the outer concrete shell wraps the functional sandwich layer, and the functional sandwich layer wraps the inner concrete shell. The outer concrete segment and the inner concrete segment are connected by a connector to form a sandwich segment; the sandwich segments are connected by annular joints to form a segment ring; the segment rings are connected by longitudinal joints to form a sandwich shell. The connectors between the inner and outer segments and the joints between the sandwich segments and the segment rings in the concrete sandwich shell structure of the present invention can ensure that the inner and outer shells work together to withstand external loads. The functional sandwich layer can play a functional role such as vibration reduction and noise reduction. Its material is lighter than concrete and can greatly reduce the deadweight of the sandwich shell structure. The structure of the present invention can be widely used in structures such as subways, roads, and undersea tunnels.

Description

Technical Field

[0001] The invention relates to the technical field of shield tunnel lining segments and concrete, and in particular to a concrete sandwich shell structure and a design and preparation method thereof. Background Art

[0002] Domestic and foreign researchers have conducted relevant research from the aspects of functional layer, shield tunnel lining segments, concrete sandwich panels, etc. In terms of vibration reduction and noise reduction, the vibration reduction and noise reduction measures currently adopted at home and abroad are mainly divided into two categories: vibration reduction at the vibration source and vibration reduction during the propagation process. The method of setting up a functional layer belongs to the second category. Existing studies at home and abroad have shown that adding a functional layer to the tunnel structure can achieve functions such as vibration reduction and noise reduction, and this method is feasible. However, the current research in this field mainly focuses on the development of new materials, optimization of the thickness and position of the functional layer, and the functional layer is placed outside the segment.

[0003] Researchers at home and abroad have also conducted a lot of research on lining segments and joints. Currently, they focus on developing new structures and joint forms and further improving existing models to better simulate the response of segments and joints under complex stresses.

[0004] In the research of concrete sandwich panel structure, foreign scholars started the relevant research relatively early and achieved certain research results. At present, the research in this field is still more focused on new connectors, new theoretical models and optimization of plate structures.

[0005] In summary, the functional layer and the load-bearing layer are separated in traditional structures. Although their respective research is relatively active, they belong to different fields and are relatively independent. They also need to be installed separately during construction, and the process is relatively complicated, which leads to certain restrictions on the application of the functional layer and the potential is not fully utilized. Multifunctional structures (such as concrete sandwich panels) have their unique advantages, but they are currently limited to energy-saving and heat-insulating construction fields such as panels and wall panels, and have not been used in infrastructure such as tunnel shells. Summary of the invention

[0006] The embodiments of the present invention provide a concrete sandwich shell structure and a design and preparation method thereof, which can realize the integration of load bearing and functionality (vibration reduction, noise reduction).

[0007] In order to achieve the above object, the present invention adopts the following technical scheme.

[0008] According to one aspect of the present invention, there is provided a concrete sandwich shell structure, comprising: an outer concrete shell, a vibration and noise reduction sandwich layer, and an inner concrete shell;

[0009] The outer concrete shell wraps the functional sandwich layer, and the functional sandwich layer wraps the inner concrete shell. The outer concrete segment and the inner concrete segment are connected by a connecting piece.

[0010] Preferably, it includes:

[0011] The upper and lower ends of the curved grid type connector or the curved plate connector are respectively embedded in the outer concrete segment and the inner concrete segment, and the outer concrete segment and the inner concrete shell are connected to form a sandwich segment through the curved grid type connector or the curved plate connector.

[0012] Preferably, the sandwich segments are connected together via annular joints with a certain rigidity to form a sandwich segment ring.

[0013] Preferably, a longitudinal joint is provided in the longitudinal direction of the tunnel, and the longitudinal joint connects the sandwich segment rings to form a sandwich shell.

[0014] Preferably, the sandwich segments with connectors are prefabricated in a prefabrication plant. During installation, the sandwich segments are connected together in the annular direction through annular joints to form a segment ring, and in the longitudinal direction through longitudinal joints to form a sandwich shell.

[0015] Preferably, the entire concrete sandwich shell structure is a shell structure formed by connecting the connectors inside the sandwich segments, the annular joints between the sandwich segments, and the longitudinal joints between the segment rings.

[0016] According to another aspect of the present invention, a design method for a concrete sandwich shell structure is provided, characterized in that, applied to the concrete sandwich shell structure, the method comprises:

[0017] Based on the shear lag and composite effect of the curved interlayer connectors, a concrete sandwich segment model is established according to the cylindrical shell theory.

[0018] The stiffness and strength of the concrete sandwich segment are calculated according to the concrete sandwich segment model, and the deformation and maximum bearing capacity of the concrete sandwich segment are predicted.

[0019] Preferably, the concrete sandwich segment model is established based on the shear lag and composite effect generated by the curved interlayer connector according to the cylindrical shell theory, including:

[0020] The composite effect of the concrete sandwich segment structure depends on the internal force transmitted by the curved connector between the outer concrete segment and the inner concrete segment. If the stiffness of the connector is large enough to transmit 100% of the internal force, the composite effect is 100% and the slip between the two surface layers is zero; if the stiffness of the connector is zero, the internal force cannot be transmitted, the composite effect is zero, and there is no connection between the two surface layers; if the connector has finite stiffness, finite slip will occur between the two surface layers, which is called partial composite effect, and its value depends on the stiffness of the connector;

[0021] Assume that the radii of the outer and inner concrete segments are R1 and R2 respectively, and the width is b. Assume that the inner and outer segments are connected by connectors at x = 0 and x = b. The external load and internal force components acting on the microelement of the outer segment form a balanced force system. According to the equilibrium condition, the relationship of the balanced force system is:

[0022]

[0023]

[0024] T2=R2q3 (3)

[0025] Where q1, q2 and q3 are external loads along the tangent and normal directions; T1, T2 and S are normal stress and shear stress.

[0026] Preferably, the step of calculating the stiffness and strength of the concrete sandwich segment according to the concrete sandwich segment model and predicting the deformation and maximum bearing capacity of the concrete sandwich segment comprises:

[0027] According to the boundary conditions, at the contact surface between the connector and the segment (x=0, b), there is a balance between the stress in the segment and the stress in the connector, and the shear force of the segment at the connector is the largest. The shear force decreases as the distance from the connector increases, forming a shear lag effect.

[0028] According to the coordination condition that the difference in strain between the inner and outer segments at the connector is equal to the difference in strain between the upper and lower segments of the connector, the relationship between the strain, displacement and internal force of the inner and outer segments represented by the composite effect and the relationship between the strain, displacement and internal force in the connector are obtained by solving the relationship equation of the equilibrium force system according to the physical relationship and the geometric relationship;

[0029] Based on the relationship between the strain, displacement and internal force of the inner and outer layer segments, and the relationship between the strain, displacement and internal force in the connecting parts, the stiffness and strength of the concrete sandwich segment are calculated through the effective width, and the deformation and maximum bearing capacity of the concrete sandwich segment are predicted using traditional shell theory based on the calculated stiffness and strength.

[0030] Preferably, the method further comprises:

[0031] The sandwich segments are connected together through annular joints with a certain stiffness to form a segment ring, and the segment rings along the longitudinal direction of the tunnel are connected together through longitudinal joints with a certain stiffness to form a sandwich shell. The composite coefficient is introduced into the theory of the joints of the segment rings. Taking the bending stiffness as an example, a 100% composite effect indicates that there is no relative rotation angle between the two segments, and its effect is equivalent to a solid segment ring without joints; a 0% composite effect means that the two segments can rotate freely, which is equivalent to an ideal hinge between the segments. A unified theoretical model of concrete sandwich shell based on the composite effect is established, which takes into account the interlayer connectors, annular and longitudinal segment joint stiffness.

[0032] According to another aspect of the present invention, a method for preparing a concrete sandwich shell structure is provided, characterized in that the method is applied to the concrete sandwich shell structure and comprises:

[0033] Step 1, making the steel skeleton of the inner and outer layers of the sandwich segment;

[0034] The inner layer is the inner concrete segment, and the outer layer is the outer concrete segment;

[0035] Step 2: Hang the inner steel bar skeleton into the mold at the designated position of the steel bar skeleton;

[0036] Step 3: After the concrete of the inner concrete segment is stirred, it will be sent into the mold, and then the concrete of the inner concrete segment will be vibrated;

[0037] Step 4: When the inner concrete is still wet, insert one end of the connector into the inner concrete;

[0038] Step 5: After the inner layer concrete reaches a certain strength, install the vibration and noise reduction sandwich layer of the functional layer;

[0039] Step 6: Hang the outer steel bar skeleton into the mold at the designated position of the steel bar skeleton;

[0040] Step 7: After the concrete of the outer concrete segment is stirred, it will be sent into the mold, and then the concrete of the outer concrete segment will be vibrated;

[0041] In step 4, the connector has been fixed. When pouring the outer layer of concrete, the concrete will wrap around the other end of the connector;

[0042] Step 8: Maintenance;

[0043] Step 9: demoulding;

[0044] Step 10: Transferring the sandwich segments;

[0045] Step 11: Maintenance of sandwich segments.

[0046] It can be seen from the technical solutions provided by the above-mentioned embodiments of the present invention that the connectors between the inner and outer layer segments, the sandwich segment joints, and the sandwich segment ring joints in the concrete sandwich shell structure of the embodiments of the present invention can ensure that the two shells work together to bear external loads, and the strength and stiffness can be equivalent to those of a solid concrete shell, which is suitable for the large aperture requirements of underground tunnels. The functional sandwich layer can play a functional role such as vibration reduction and noise reduction. Its material is lighter than concrete and can greatly reduce the deadweight of the sandwich shell structure. Since the sandwich layer is located in the middle of the structure, the total thickness of the sandwich shell is thinner than that of a traditional tunnel structure in which the functional layer is outside the segment, which can expand the available space.

[0047] Additional aspects and advantages of the present invention will be given in part in the following description, which will become obvious from the following description, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0049] Figure 1 A schematic cross-sectional view of a concrete sandwich shell structure with annular joints provided in an embodiment of the present invention.

[0050] Figure 2 A cross-sectional schematic diagram of a concrete sandwich segment structure provided in an embodiment of the present invention.

[0051] Figure 3 A three-dimensional diagram of a concrete sandwich shell structure provided in an embodiment of the present invention.

[0052] Figure 4 A structural diagram of a curved grid-type connector provided in an embodiment of the present invention.

[0053] Figure 5 A structural diagram of a curved plate connector provided in an embodiment of the present invention.

[0054] Figure 6 A three-dimensional diagram of a sandwich shell structure with circumferential and longitudinal joints provided in an embodiment of the present invention.

[0055] FIG7 is a schematic diagram of a shell differential equation provided by an embodiment of the present invention;

[0056] Figure 8 A schematic diagram of a shear lag effect provided by an embodiment of the present invention;

[0057] Fig. 9A schematic diagram of a sandwich shell model provided by an embodiment of the present invention;

[0058] Fig.10 A schematic diagram of an inner and outer layer connecting member model provided in an embodiment of the present invention.

[0059] In the figure, there are outer concrete segments 1, functional sandwich layers 2, inner concrete segments 3, connectors 4 between inner and outer segments, curved grid connectors 5, curved plate connectors with holes at the upper and lower ends 6, annular joints 7, sandwich segments 8, and longitudinal joints 9. DETAILED DESCRIPTION

[0060] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0061] Those skilled in the art will appreciate that, unless expressly stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, the "connection" or "coupling" used herein may include wireless connection or coupling. The term "or" used herein includes any unit and all combinations of one or more associated listed items.

[0062] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0063] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings, and each embodiment does not constitute a limitation on the embodiments of the present invention.

[0064] Embodiment 1

[0065] An embodiment of the present invention proposes a green concrete sandwich shell structure that integrates load-bearing and functionality (vibration reduction, noise reduction), adopts inner and outer concrete shells and a built-in sandwich functional layer structure, and the two layers of concrete shells are connected by connecting parts inside the sandwich segments, annular joints between sandwich segments, and longitudinal joints between sandwich segment rings, thereby achieving a composite effect of inner and outer shells.

[0066] The cross-sectional schematic diagram of the concrete sandwich shell structure of the present invention is as follows Figure 1 As shown, the outer concrete segment 1 wraps the functional sandwich layer 2, and the functional sandwich layer 2 wraps the inner concrete segment 3.

[0067] The upper and lower ends of the curved grid type connector 5, the curved plate connector 6, or other forms of connectors are respectively embedded in the outer concrete segment 1 and the inner concrete segment 3, and the outer concrete segment 1 and the inner concrete segment 3 are connected to form a sandwich segment 8 through the curved grid type connector 5, the curved plate connector 6, or other forms of connectors. Figure 2 A cross-sectional schematic diagram of a concrete sandwich segment structure provided in an embodiment of the present invention. Figure 4 A structural diagram of a curved grid type connector provided in an embodiment of the present invention, Figure 5 A structural diagram of a curved plate connector provided in an embodiment of the present invention.

[0068] The sandwich segments 8 are connected together by annular joints 7 with a certain rigidity to form a sandwich segment ring. The sandwich segment ring is connected by longitudinal joints 9 to form a sandwich shell. Figure 3 A three-dimensional diagram of a concrete sandwich shell structure provided in an embodiment of the present invention. Figure 6 A three-dimensional diagram of a sandwich shell structure with circumferential and longitudinal joints provided in an embodiment of the present invention.

[0069] During on-site installation, each sandwich segment 8 is connected together in the circumferential direction through the circumferential joint 7 to form a segment ring. The segment ring is connected together in the longitudinal direction through the longitudinal joint 9 to form a sandwich shell. The sandwich segment 8 with the connector 4 is prefabricated in a prefabrication plant, and the circumferential joint 7 and the longitudinal joint 9 connecting each sandwich segment 8 can be the same as the joints of the conventional shield segment.

[0070] Embodiment 2

[0071] Concrete sandwich shell theory is the basis of the entire research. To this end, based on the consideration of material and geometric nonlinearity, the present invention intends to systematically carry out work in the following aspects:

[0072] 1: Research on the analysis theory of concrete sandwich shell. Using shell theory, the concrete sandwich segment theory is established by considering the shear lag and composite effect of the curved interlayer connectors; on the basis of the segment theory, the concrete sandwich segment ring theory is established by considering the composite effect between the joints between the segments; on the basis of the segment ring theory, the concrete sandwich shell theory is established by considering the composite effect between the segment ring joints;

[0073] 2: Research on the structural form and stress mechanism of concrete sandwich shell connectors. Use elastic-plastic mechanics to establish the curved interlayer connector and inter-segment joint model, and introduce the composite effect to describe its connection function.

[0074] 3: Research on the performance and structural optimization of concrete sandwich shell structures. Through theoretical research and experimental / numerical simulation verification, a prototype concrete sandwich shell structure is proposed using optimization technology.

[0075] (1) Basic theoretical research on concrete sandwich shell structure

[0076] 1) Concrete sandwich segment model

[0077] The theoretical model of concrete sandwich segments is based on the cylindrical shell theory, and the shear lag and composite effect generated by the curved interlayer connectors must be considered. The composite effect (Degree of Composite Action, DCA) depends on the internal force transmitted by the connector between the two surface layers. The present invention defines a DCA suitable for sandwich structures. If the stiffness of the connector is large enough to transmit 100% of the internal force, the DCA is 100% and the slip between the two surface layers is zero. At this time, the sandwich structure is equivalent to a solid structure. On the contrary, if the stiffness of the connector is zero, the internal force cannot be transmitted, the composite effect is zero, and there is no connection between the two surface layers. If the connector has finite stiffness, in order to maintain strain coordination, a finite slip will occur between the two surface layers, which is called a partial composite effect, and its value depends on the stiffness of the connector.

[0078] FIG7 is a schematic diagram of a shell differential equation provided by an embodiment of the present invention, FIG7(a) is a schematic diagram of a concrete sandwich segment, FIG7(b) is a schematic diagram of a single-layer segment microelement, and FIG7(c) is a segment-connector interaction. As shown in FIG7(a), the radii of the inner and outer segments are R1 and R2, respectively, and the width is b. Assume that the inner and outer segments are connected by connectors at x=0 and x=b. Acting on the outer segment microelement ( Figure 7b ) and the internal force components form a balanced force system. According to the equilibrium condition, the relationship between the balanced force system is:

[0079]

[0080]

[0081] T2=R2q3 (3)

[0082] Where q1, q2 and q3 are external loads along the tangent and normal directions; T1, T2 and S are normal stress and shear stress.

[0083] As shown in Figure 7(c), according to the boundary conditions, at the contact surface between the connector and the segment (x=0, b), there is a balance between the stress in the segment and the stress in the connector, and the shear force of the segment is the largest at the connector. The shear force decreases as the distance from the connector increases, forming a shear lag effect. Figure 8 A schematic diagram of a shear lag effect provided by an embodiment of the present invention is shown in FIG. Figure 8 As shown. According to the physical relationship and geometric relationship, the relationship between the strain, displacement and internal force of the inner and outer segments can be obtained by solving the relationship of the equilibrium force system. Similarly, the relationship between the strain, displacement and internal force in the connector can be obtained. They are related to the stiffness K of the connector and can be expressed by DCA. At the connector, the difference between the strain of the inner and outer segments is equal to the difference between the upper and lower strains of the connector. According to this deformation coordination condition, the final result can be solved.

[0084] The effective width is an important parameter to describe the shear lag effect. This invention introduces the concepts of effective flange width of bridges and effective width of concrete sandwich panels into the analysis of concrete sandwich segments. Figure 8 As shown in (b), through the effective width and composite effect, this theory can calculate the stiffness and strength of the concrete sandwich segment, and predict its deformation and maximum bearing capacity.

[0085] Based on the relationship between the strain, displacement and internal force of the inner and outer segments, and the relationship between the strain, displacement and internal force in the connector, the stiffness and strength of the concrete sandwich segment are calculated through the effective width. Based on the calculated stiffness and strength, the deformation and maximum bearing capacity of the concrete sandwich segment can be predicted using traditional shell theory.

[0086] 2) Concrete sandwich segment ring and sandwich shell model considering the influence of joints

[0087] Fig. 9 A schematic diagram of a sandwich shell model provided by an embodiment of the present invention, Fig. 9 (a) is a three-dimensional graph. Fig. 9 (b) is a cross-sectional view. Fig. 9As shown, the sandwich segments are connected together by annular joints with a certain rigidity to form a segment ring, and the segment rings along the longitudinal direction of the tunnel are connected together by longitudinal joints with a certain rigidity to form a sandwich shell. The present invention further introduces the composite coefficient into the theory of joints. Taking bending stiffness as an example, 100% DCA indicates that there is no relative rotation angle between the two segments, and its effect is equivalent to a solid segment ring without joints. 0% DCA means that the two segments can rotate freely, which is equivalent to an ideal hinge between the segments. On the basis of the segment theory, the concrete sandwich segment ring theory is established by considering the composite effect between the annular joints between the segments; on the basis of the segment ring theory, the unified theoretical model of the concrete sandwich shell lining segment tunnel is established by considering the composite effect between the longitudinal joints of the segment ring. In this model, the main loads will be considered, including: earth pressure, water pressure, overload, self-weight, vertical foundation reaction force and distributed horizontal resistance.

[0088] 3) Inner and outer layer connector model

[0089] Fig.10 A schematic diagram of an inner and outer layer segment connector model provided in an embodiment of the present invention. The connector can be made of a variety of materials, including steel, carbon fiber reinforced polymer (CFRP), glass fiber reinforced polymer (GFRP), etc. The connector can be in the form of a plate type, a grid type, etc. Fig.10 As shown in (b). Fig.10 The interlayer connector is analyzed using the coordinate system and stress state shown in (a). Taking microelement can establish equilibrium equation. The relationship between external force and strain and displacement can be obtained by using physical equations and geometric equations. Thus, the characteristics of the connector under tension, compression and shear can be obtained.

[0090] 4) Structural optimization

[0091] Based on this theoretical analysis, a large number of parameter analyses will be conducted to optimize the multifunctional concrete sandwich shell. The parameters considered for optimization include the thickness of the inner and outer concrete shells and the sandwich layer, the type, quantity and configuration of the connectors, and the configuration of the reinforcement.

[0092] Practice has proved that concrete sandwich structures can achieve 100% DCA and achieve stiffness and strength comparable to solid structures.

[0093] The use of damping interlayers in double-layer shells has a very good effect on vibration suppression. Since the damping material has a small stiffness, when the structure vibrates, its energy can be immediately transferred to the damping material, causing the mutual displacement and friction of the molecular chains inside the damping material, so that part of the vibration energy is converted into heat energy, thereby reducing the vibration of the shell and achieving the purpose of vibration reduction and noise reduction.

[0094] The invention achieves the purpose of vibration reduction and noise reduction by adopting a multifunctional reinforced concrete sandwich shell as the type of shield tunnel lining segment.

[0095] Embodiment 3

[0096] The manufacture of concrete sandwich segments can use existing traditional segment molds. The difference is that traditional segments are formed in one step, while concrete sandwich segments require first casting the inner segment, installing the sandwich layer and connectors, and then casting the outer segment.

[0097] The method for preparing the concrete sandwich shell structure according to the embodiment of the present invention comprises the following processing steps:

[0098] Step 1: Make the inner and outer steel skeletons.

[0099] The inner layer is the inner concrete segment, and the outer layer is the outer concrete segment. The steel skeleton is used to withstand tension and work together with concrete to form a reinforced concrete structure, increasing the strength of the structure.

[0100] Step 2: Assemble the mold and install the inner steel frame.

[0101] The mold can be a steel mold, and the shape and size must meet the requirements of the sandwich segment. The inner layer steel frame is hung into the mold at the designated position of the steel frame.

[0102] Step 3: pour the concrete of the inner concrete segment and vibrate the concrete of the inner concrete segment.

[0103] After the concrete of the inner concrete segment is mixed, it will be sent into the mold, and then the concrete of the inner concrete segment will be vibrated.

[0104] Step 4: Install the connector.

[0105] While the inner concrete is still wet, insert one end of the connector into the concrete.

[0106] Step 5: After the concrete reaches a certain strength, install the vibration and noise reduction sandwich layer of the functional layer.

[0107] The material of the shock-absorbing and noise-reducing layer can be foam concrete, asphalt, rubber, EPS, etc. It can be prefabricated in advance and then installed above the inner layer of concrete.

[0108] Step 6: Install the outer concrete segment steel frame.

[0109] Hang the outer steel bar skeleton into the mold at the designated position of the steel bar skeleton.

[0110] Step 7: Pour the outer layer of segment concrete, vibrate the concrete, and then smooth it.

[0111] After the concrete of the outer concrete segment is mixed, it will be sent into the mold, and then the concrete of the outer concrete segment will be vibrated.

[0112] In step 4, the connector has been fixed. When pouring the outer layer of concrete, the concrete will wrap around the other end of the connector;

[0113] Step 8: Maintenance.

[0114] Steam curing can be used.

[0115] Step 9: Remove the mold.

[0116] Step 10: Transfer the sandwich segments.

[0117] Step 11: Maintenance of sandwich segments.

[0118] Steps 8 to 11 may be the same as the conventional shield segment construction method.

[0119] Embodiment 4 Installation method of concrete sandwich shell

[0120] During on-site installation, the sandwich segments are connected together in the circumferential direction through circumferential joints to form a segment ring, and the segment rings are connected together in the longitudinal direction through longitudinal joints to form a sandwich shell.

[0121] The concrete sandwich shell structure of the embodiment of the present invention can be applied to structures such as subways, highways, and submarine tunnels, and is particularly suitable for urban underground tunnels, shallow buried tunnels, new tunnels built near existing tunnels, and other occasions with high requirements on vibration and noise.

[0122] In summary, the present invention has a positive significance for the theoretical innovation of green multifunctional structures and the promotion of this new type of structure, thereby promoting the further improvement of the innovation-driven modern integrated transportation system. Compared with the traditional structure, the concrete sandwich shell structure of the present invention has the following advantages:

[0123] High strength: The connectors between the inner and outer segments, the annular joints between the sandwich segments, and the longitudinal joints between the sandwich segment rings can ensure the coordinated work between the two shells. The strength and stiffness are comparable to those of a solid concrete shell, which is suitable for large-aperture requirements of underground tunnels.

[0124] Lightweight: Functional sandwich layer materials include foam concrete, rubber, etc., which are lighter than concrete and can greatly reduce the self-weight of the sandwich segment structure, which is conducive to the transportation of prefabricated segments.

[0125] Saving available space: Since the sandwich layer is located in the middle of the structure, the total thickness is thinner than the traditional structure in which the functional layer is located outside the tube segment, which can expand the available space.

[0126] Good durability: In traditional tunnel structures, the functional layer and the load-bearing structure are separated, which causes some problems. In the concrete sandwich shell, the functional layer is located in the middle of the concrete shell, and the concrete can provide better durability and support, thereby greatly improving the durability and integrity of the structure.

[0127] Convenient construction and low cost: In traditional structures, the functional layer and lining segments need to be installed separately. Concrete sandwich segments can greatly simplify the installation process and reduce the construction cost.

[0128] Convenient production: The concrete sandwich segment can be manufactured using the existing traditional segment mold. The difference is that the traditional segment is formed in one step, while the concrete sandwich segment needs to cast the inner segment first, install the sandwich layer and connectors, and then cast the outer segment.

[0129] Those skilled in the art can understand that the accompanying drawings are only schematic diagrams of an embodiment, and the modules or processes in the accompanying drawings are not necessarily required to implement the present invention.

[0130] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The device and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0131] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A design method for a concrete sandwich shell structure, characterized in that: The concrete sandwich shell structure comprises: an outer concrete shell, a vibration and noise reduction sandwich layer and an inner concrete shell; The outer concrete shell wraps the vibration-reducing and noise-reducing sandwich layer, the vibration-reducing and noise-reducing sandwich layer wraps the inner concrete shell, and the outer concrete shell and the inner concrete shell are connected by a connecting piece; The method comprises: Based on the shear lag and composite effect of the curved interlayer connectors, a concrete sandwich segment model is established according to the cylindrical shell theory. Calculating the stiffness and strength of the concrete sandwich segment according to the concrete sandwich segment model, and predicting the deformation and maximum bearing capacity of the concrete sandwich segment; The concrete sandwich segment model is established based on the shear lag and composite effect generated by the curved interlayer connector according to the cylindrical shell theory, including: The composite effect of the concrete sandwich tube structure depends on the internal force transmitted by the curved connector between the outer concrete shell and the inner concrete shell. If the stiffness of the connector is large enough to transmit 100% of the internal force, the composite effect is 100% and the slip between the two surface layers is zero; if the stiffness of the connector is zero, the internal force cannot be transmitted, the composite effect is zero, and there is no connection between the two surface layers; if the connector has finite stiffness, finite slip will occur between the two surface layers, which is called partial composite effect, and its value depends on the stiffness of the connector; Assume that the radii of the outer and inner concrete segments are R1 and R2 respectively, and the width is b. Assume that the inner and outer segments are connected by connectors at x=0 and x=b. The external load and internal force components acting on the microelement of the outer segment constitute a balanced force system. The relationship of the balanced force system according to the equilibrium condition is: T2=R2q3 (3) Where q1 is the external load on the microelement along the axial tangent direction, q2 is the external load on the microelement along the circumferential tangent direction, q3 is the external load on the microelement along the radial normal direction; T1 is the normal stress on the microelement along the axial direction, T2 is the normal stress on the microelement along the circumferential direction, S is the shear stress in the microelement plane, x is the coordinate variable along the axial direction in the coordinate system, and θ is the coordinate variable along the circumferential direction in the coordinate system.

2. The method according to claim 1, characterized in that The upper and lower ends of the curved grid type connector or the curved plate connector in the concrete sandwich shell structure are respectively embedded in the outer concrete segment and the inner concrete segment, and the outer concrete shell and the inner concrete shell are connected to form a sandwich segment through the curved grid type connector or the curved plate connector.

3. The method according to claim 2, characterized in that The sandwich segments in the concrete sandwich shell structure are connected together through annular joints with a certain rigidity to form a sandwich segment ring.

4. The method according to claim 3, characterized in that A longitudinal joint is arranged in the tunnel longitudinal direction in the concrete sandwich shell structure, and the longitudinal joint connects the sandwich segment rings to form a sandwich shell.

5. The method according to claim 3 or 4, characterized in that: The sandwich segments with connectors in the concrete sandwich shell structure are prefabricated in a prefabrication plant. During installation, the sandwich segments are connected together in the annular direction through annular joints to form a segment ring, and in the longitudinal direction through longitudinal joints to form a sandwich shell.

6. The method according to claim 5, characterized in that The entire concrete sandwich shell structure in the concrete sandwich shell structure is a shell structure formed by connecting the connectors inside the sandwich segments, the annular joints between the sandwich segments, and the longitudinal joints between the segment rings.

7. The method according to claim 1, characterized in that The method of calculating the stiffness and strength of the concrete sandwich segment according to the concrete sandwich segment model and predicting the deformation and maximum bearing capacity of the concrete sandwich segment includes: According to the boundary conditions, at the contact surface between the connector and the segment, there is a balance between the stress in the segment and the stress in the connector, and the shear force of the segment at the connector is the largest. The shear force decreases as the distance from the connector increases, forming a shear lag effect. According to the coordination condition that the difference in strain between the inner and outer segments at the connector is equal to the difference in strain between the upper and lower segments of the connector, the relationship between the strain, displacement and internal force of the inner and outer segments represented by the composite effect and the relationship between the strain, displacement and internal force in the connector are obtained by solving the relationship equation of the equilibrium force system according to the physical relationship and the geometric relationship; Based on the relationship between the strain, displacement and internal force of the inner and outer layer segments, and the relationship between the strain, displacement and internal force in the connecting parts, the stiffness and strength of the concrete sandwich segment are calculated through the effective width, and the deformation and maximum bearing capacity of the concrete sandwich segment are predicted using traditional shell theory based on the calculated stiffness and strength.

8. The method according to claim 6 or 7, characterized in that: The method further comprises: The sandwich segments are connected together through annular joints with a certain stiffness to form a segment ring, and the segment rings along the longitudinal direction of the tunnel are connected together through longitudinal joints with a certain stiffness to form a sandwich shell. The composite coefficient is introduced into the theory of the joints of the segment rings. For the bending stiffness, 100% composite effect indicates that there is no relative rotation angle between the two segments, and its effect is equivalent to a solid segment ring without joints; 0% composite effect means that the two segments can rotate freely, which is equivalent to an ideal hinge between the segments. A unified theoretical model of concrete sandwich shell based on composite effect is established, which takes into account the interlayer connectors, annular and longitudinal segment joint stiffness.

9. A method for preparing a concrete sandwich shell structure, characterized in that: Based on the design method of the concrete sandwich shell structure according to any one of claims 1 to 8, the preparation method comprises: Step 1, making the steel skeleton of the inner and outer layers of the sandwich segment; The inner layer is the inner concrete segment, and the outer layer is the outer concrete segment; Step 2: Hang the inner steel bar skeleton into the mold at the designated position of the steel bar skeleton; Step 3: After the concrete of the inner concrete segment is stirred, it will be sent into the mold, and then the concrete of the inner concrete segment will be vibrated; Step 4: When the inner concrete is still wet, insert one end of the connector into the inner concrete; Step 5: After the inner layer concrete reaches a certain strength, install the vibration and noise reduction sandwich layer of the functional layer; Step 6: Hang the outer steel bar skeleton into the mold at the designated position of the steel bar skeleton; Step 7: After the concrete of the outer concrete segment is stirred, it will be sent into the mold, and then the concrete of the outer concrete segment will be vibrated; When pouring the outer layer of concrete, the outer layer of concrete will wrap around the other end of the connector; Step 8: Maintenance; Step 9: demoulding; Step 10: Transferring the sandwich segments; Step 11: Maintenance of sandwich segments.

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