Periodic row pile structure with vibration isolation and support and construction method

Abstract

The application discloses a periodic pile row structure with vibration isolation and support and a construction method, which comprises a pile body assembly, a connecting assembly, and a first pile row and a second pile row. The periodic pile row structure is used for support, and the vibration isolation effect of the structure on the vibration caused by the surrounding rail transit vehicle is considered in advance, so that the structure can protect the stability of the surrounding soil during the building construction stage, thereby playing a supporting role, and can also be used as a periodic structure barrier for rail transit, thereby playing a vibration isolation role. The structure can prevent the influence of train-induced vibration on the safety of building construction during the building construction stage, and can reduce the influence of train-induced vibration on the comfort of human habitation of the building during the building operation stage. Meanwhile, the engineering quantity is reduced, the cost is reduced, the economic efficiency is better, and the effect of the pile row is widened.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building deep foundation pit support and rail transit vibration isolation technology, and relates to a periodic row pile structure with vibration isolation and support and a construction method. BACKGROUND

[0002] With the increasing scale of underground space development and the increasing complexity of the surrounding environment, the requirements for deep foundation pit support technology are also increasing. During the construction of the foundation pit of a building, soil compaction, blasting and other processes carried out in the construction site will inevitably have a great impact on the lives of surrounding residents and surrounding buildings. In addition, the vibration of rail transit outside the site will also affect the safety of the construction site and the accuracy of instrument measurement. With the further densification of the urban rail transit network, more and more problems caused by environmental vibration will inevitably occur. The existing control methods for urban rail transit environmental vibration can be roughly divided into three categories: vibration source damping measures: vehicle damping, reasonable maintenance of wheel and track structure, and use of damping track; transmission path damping measures: continuous or discontinuous barriers such as trenches, row piles, sheet pile walls, and wave blocks are used to cut off, scatter, and diffract vibration waves to achieve vibration isolation or to attenuate vibration by piling heavy objects beside the track; passive vibration isolation measures: vibration isolation devices are installed on newly built buildings or existing equipment. Common transmission path damping measures for rail transit include elastic foundation, open trench or empty trench, filled trench, row pile, and wave block, among which row pile is widely concerned due to its advantages of fast construction speed, low cost, and low requirement for barrier embedding depth in low-frequency vibration isolation.

[0003] The existing deep foundation pit support technology and rail transit discontinuous barrier damping technology generally only have their corresponding single function, so a periodic row pile structure with vibration isolation and support is proposed, and a practical and effective support and damping design method is proposed, which is of great significance for the development of theoretical research and the solution of practical problems. SUMMARY

[0004] This section aims to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, abstract and title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0005] In view of the problems in the prior art, the present application is proposed.

[0006] Therefore, the technical problem to be solved by the present application is that the existing deep foundation pit support technology and rail transit discontinuous barrier damping technology generally only have their corresponding single function, and the damping and support procedures require more work, which delays the construction period.

[0007] To solve the above technical problems, the present application provides the following technical solutions: a periodic pile row structure with vibration isolation and support, comprising a pile body assembly, the pile body assembly comprising a first pile row and a second pile row, the first pile row being arranged on one side of the second pile row;

[0008] A connecting assembly is connected with the pile body assembly and comprises a connecting beam and a crown beam, the crown beam connecting each single pile in the first pile row and the second pile row, and the connecting beam connecting the first pile row and the second pile row.

[0009] As a preferred scheme of the periodic pile row structure with vibration isolation and support, the first pile row is a prefabricated pile made of a single material, and the second pile row is a composite prefabricated pile made of two materials and comprises a pile body and a wrapping layer.

[0010] As a preferred scheme of the periodic pile row structure with vibration isolation and support, the connecting beam and the crown beam are used to transmit shear force and bending moment between the first pile row and the second pile row, and the crown beam is used to increase the rigidity of the structure and constrain the deformation of the pile top.

[0011] The pile body assembly is arranged in a plum blossom type alternately.

[0012] As a preferred scheme of the periodic pile row structure with vibration isolation and support, each single pile in the first pile row is connected through a crown beam, each single pile in the second pile row is also connected through a crown beam, and adjacent single piles in the first pile row and the second pile row are alternately connected through a connecting beam, so that the pile body assembly forms a better whole.

[0013] As a preferred scheme of the periodic pile row structure with vibration isolation and support, the center distance between each single pile in the first pile row and the second pile row is not greater than 2 times the diameter of the pile, and the reasonable range of the row distance is 2-5 times the diameter of the pile.

[0014] To solve the above technical problems, the present application provides the following technical solutions: a periodic pile row construction method with vibration isolation and support, comprising

[0015] Foundation pit dewatering;

[0016] Foundation pile hole forming;

[0017] Pile row structure pile hole construction;

[0018] Crown beam and connecting beam construction;

[0019] Wet connection of double-pile-row joints;

[0020] Foundation pit excavation;

[0021] Hanging of steel mesh between piles and spraying of concrete.

[0022] As a preferred scheme of the periodic pile row construction method with vibration isolation and support, the plum blossom type arrangement of the pile row structure improves the pile body density of the pile row barrier system while using the minimum number of piles.

[0023] As a preferred scheme of the periodic pile row construction method with vibration isolation and support, the plum blossom type arrangement of the pile row structure improves the pile body density of the pile row barrier system while using the minimum number of piles.

[0024] As a preferred scheme of the periodic pile row construction method with vibration isolation and support, the plum blossom type arrangement of the pile row structure improves the pile body density of the pile row barrier system while using the minimum number of piles.

[0025] As a preferred scheme of the periodic pile row construction method with vibration isolation and support, the plum blossom type arrangement of the pile row structure improves the pile body density of the pile row barrier system while using the minimum number of piles.

[0026] The periodic pile row structure is used for support, and the vibration isolation effect of the structure on the surrounding rail transit vehicle-induced vibration is considered in advance, so that the structure protects the stability of the surrounding soil during the building construction phase, thereby playing a supporting role, and can also be used as a periodic structure barrier for rail transit, thereby playing a vibration isolation role. The structure can prevent the influence of train-induced vibration on the safety of building construction during the building construction phase, and can reduce the influence of train-induced vibration on the comfort of building occupancy during the building operation phase, while reducing the engineering quantity and cost, having better economic efficiency, and widening the effect of pile support. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor. Among them:

[0028] Figure 1 It is a schematic diagram of the overall device of the present application.

[0029] Figure 2 It is a schematic diagram of the device installation of the present application. DETAILED DESCRIPTION

[0030] In order to make the above objectives, features and advantages of the present application more obvious and comprehensible, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0031] In the following description, a lot of specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in other manners different from those described herein, and those skilled in the art can make similar generalizations without departing from the spirit and scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0032] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an embodiment that is independent or alternative to other embodiments.

[0033] Embodiment 1

[0034] Reference Figure 1 , Figure 2 For the first embodiment of the present application, the embodiment provides a periodic row pile structure with vibration isolation and support, including a pile body assembly 100, a connecting assembly 200, the pile body assembly 100 including a first row of piles 101 and a second row of piles 102, the first row of piles 101 being arranged on one side of the second row of piles 102.

[0035] Further, the connecting assembly 200 is connected with the pile body assembly 100, including a connecting beam 201 and a crown beam 202, the crown beam 202 connecting each single pile in the first row of piles 101 and the second row of piles 102, and the connecting beam 201 connecting the first row of piles 101 and the second row of piles 102.

[0036] Further, the first row of piles 101 is a prefabricated pile of a single material, usually a concrete prefabricated pile. The second row of piles 102 is a composite prefabricated pile made of two materials, divided into a pile body 102a and a wrapping layer 102b. The wrapping layer material used in the composite prefabricated pile needs to have a large difference from the pile body material, based on the local resonance mechanism to control the propagation of low-frequency vibration waves. Usually, in order to facilitate construction, a concrete pipe pile filled with rubber, soil particles or other materials can be used.

[0037] Further, the connecting beam 201 and the crown beam 202 are used to transfer shear force and bending moment between the first row of piles 101 and the second row of piles 102, and the crown beam 202 is used to increase the stiffness of the structure and constrain the deformation of the pile top.

[0038] The pile body assembly 100 is arranged in a quincunx pattern, which can improve the pile body density of the pile barrier system with the least number of piles, and the periodic pile arrangement can obtain a wider attenuation domain, thereby achieving more obvious vibration isolation and reduction effect.

[0039] The single piles in the first row of piles 101 are connected by the crown beams 202, the single piles in the second row of piles 102 are also connected by the crown beams 202, and the adjacent single piles in the first row of piles 101 and the second row of piles 102 are alternately connected by the tie beams 201, so that the pile body assembly 100 forms a better whole, and the system has large lateral stiffness and overall stiffness.

[0040] Preferably, the center distance between the first row of piles 101 and the second row of piles 102 is not greater than 2 times the pile diameter, and the reasonable row distance is 2-5 times the pile diameter.

[0041] Preferably, the number of piles can be appropriately increased (three rows or more) to obtain better vibration isolation effect; secondly, the two types of piles can be combined to achieve better vibration isolation effect.

[0042] In summary, the periodic pile arrangement structure is used for support, and the vibration isolation effect on the surrounding rail transit vehicle-induced vibration is considered in advance, which can reduce the influence of train-induced vibration on the comfort of the building in the operation stage of the building, reduce the engineering quantity and cost, has better economy, and widens the effect of the pile.

[0043] Embodiment 2

[0044] Reference Figures 1-2 For the second embodiment of the application, which is based on the previous embodiment, a periodic pile construction method with vibration isolation and support is provided, specifically including,

[0045] Foundation pit dewatering;

[0046] Foundation pile hole forming;

[0047] Pile structure pile hole construction;

[0048] Crown beam and tie beam construction;

[0049] Double-row pile joint wet connection;

[0050] Foundation pit excavation;

[0051] Steel mesh between piles, and sprayed concrete

[0052] Furthermore, the staggered arrangement of the pile structure increases the pile density of the pile barrier system while minimizing the number of piles used. During the construction of the capping beam and connecting beam, precast reinforced concrete piles and precast composite piles are inserted into the pile holes to form a periodic pile structure. The foundation trenches for the capping beam and connecting beam are excavated, and the precast reinforced concrete capping beam and precast reinforced concrete connecting beam are inserted. When wet-jointing the double-row pile joints, concrete is poured at the joints between the precast reinforced concrete capping beam, the precast reinforced concrete connecting beam, and the double-row piles for wet jointing. During the excavation of the foundation pit, the excavation proceeds sequentially to the designed anchor or support positions, and the anchors or supports are constructed. When excavating to the anchor construction working surface, the height difference between the excavation surface and the anchor or soil nail should not exceed 500mm.

[0053] Example 3

[0054] Reference Figure 1 This is the third embodiment of the present invention. This embodiment is based on the previous embodiment, but the difference is that it provides periodic pile arrangement to meet the vibration reduction and support verification calculations.

[0055] Regarding the vibration isolation effect of the piles, considering an elastic wave frequency of 0–50 Hz, for a scattering type solid concrete pile, the period constant a = 2 m, the pile radius R = 650 mm, and the soil density ρ = 1900–2200 kg / m³ are taken. 3 Elastic modulus E = 2 × 10 - 2 GPa; Concrete parameters: density ρ = 2200~2500 kg / m³ 3 The elastic modulus E = 30 GPa. Calculations using Comsol software show that the elastic wave exhibits varying degrees of attenuation in most frequency ranges from 0 to 11 Hz and from 22 Hz to 50 Hz, with complete attenuation achieved in the first complete attenuation domain of 33.32 Hz to 37.34 Hz.

[0056] For a locally resonant composite pile, the period constant a = 2m, the outer radius R = 650mm, the inner radius r = 500mm, and the soil density ρ = 1900~2200kg / m³ are taken. 3 Elastic modulus E = 2 × 10 -2 GPa; Concrete parameters: density ρ = 2200~2500 kg / m³ 3 Elastic modulus E = 30 GPa; Filler material density ρ = 1900 kg / m³ 3 Elastic modulus E = 6 × 10 -3 GPa. Calculations using Comsol software show that the first complete attenuation range is approximately 30Hz–35Hz, within which elastic waves can be completely attenuated. When the elastic modulus of the filling material changes to E = 1 × 10⁻⁶, -3When the soft material is less than 0.5GPa, there is a relatively low first complete attenuation domain 16.8Hz~18Hz, while the elastic wave outside the attenuation domain has a weak attenuation effect or even amplification in a small part of the interval.

[0057] Combining the two types of piles to form a multi-row barrier can obtain a wider attenuation domain and better attenuation effect. According to the investigation, a row of piles can only reflect the attenuation domain characteristics to a small extent, for example, near the attenuation domain range, the vibration appears about 15dB attenuation. When the number of periodic row piles is increased, the vibration attenuation effect in the attenuation domain is immediately obvious, about 20dB attenuation for double-row piles, and about 33dB attenuation for four-row piles. Secondly, adjusting the filling rate, material, arrangement, and other parameters has an impact on the starting frequency, cutoff frequency, and bandwidth.

[0058] On the other hand, regarding the supporting effect of the pile, the above-mentioned working conditions of double-row piles are checked, the pile radius is 650mm, the pile spacing is 2m, the pile row spacing is 3m, the foundation pit depth is 10m, and the embedded depth is 10m.

[0059] Three layers of anchor cables are used, and the vertical spacing is 2.5m. The overbreak depth is 0.5m, that is, 3m is excavated for anchor cable construction, and then 3m is excavated for anchor cable construction, until the bottom of the pit is excavated, a total of 7 working conditions, and the stability is calculated by using the Lizheng deep foundation pit software.

[0060] [Overall stability calculation]

[0061] Calculation method: Swedish slice method

[0062] Stress state: effective stress method

[0063] Soil slice width in slice method: 1.00m

[0064] Sliding surface data

[0065] Circular arc radius (m) R = 19.274

[0066] Circular arc radius (m) R = 19.274

[0067] Circular arc radius (m) R = 19.274

[0068] Overall stability safety factor Ks = 1.553>1.30, which meets the specification requirements.

[0069] [Embedded segment foundation pit inside soil reaction force calculation]

[0070] Working condition 1:

[0071] Ps = 3596.848 ≤ Ep = 9721.252, the soil reaction force meets the requirements.

[0072] Working condition 2:

[0073] Ps = 3596.848 < Ep = 9721.252, the earth reaction force meets the requirements.

[0074] Working condition 3:

[0075] Ps = 3752.621 < Ep = 7183.453, the earth reaction force meets the requirements.

[0076] Working condition 4:

[0077] Ps = 3752.621 < Ep = 7183.453, the earth reaction force meets the requirements.

[0078] Working condition 5:

[0079] Ps = 3554.528 < Ep = 5027.792, the earth reaction force meets the requirements.

[0080] Working condition 6:

[0081] Ps = 3554.528 < Ep = 5027.792, the earth reaction force meets the requirements.

[0082] Working condition 7:

[0083] Ps = 3245.371 < Ep = 3578.404, the earth reaction force meets the requirements.

[0084] In the formula:

[0085] Ps is the resultant force of the earth reaction force on the embedded segment of the retaining member (kN);

[0086] Ep is the resultant force of the passive earth pressure on the embedded segment of the retaining member (kN).

[0087] It can be seen from the above calculation that the periodic pile row can meet the dual effects of vibration reduction and support, reduce the engineering quantity, reduce the cost, have better economy, and widen the effect of the pile row.

[0088] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions, which should be covered in the scope of the claims of the present application.

Claims

1. A periodic row of piles structure for both vibration isolation and support, characterized in that: Comprising, The pile body assembly (100) comprises a first row of piles (101) and a second row of piles (102), the first row of piles (101) is arranged on one side of the second row of piles (102); The connecting assembly (200) is connected with the pile body assembly (100) and comprises a connecting beam (201) and a crown beam (202), the crown beam (202) is connected with each single pile in the first row of piles (101) and the second row of piles (102), and the connecting beam (201) is connected with the first row of piles (101) and the second row of piles (102); The first row of piles (101) is a prefabricated pile made of a single material, generally a concrete prefabricated pile, the second row of piles (102) is a composite prefabricated pile made of two materials, which is divided into a pile body (102a) and a wrapping layer (102b), and a concrete pipe pile filled with rubber or soil particles is used for facilitating construction; The connecting beam (201) is used for transmitting shear force and bending moment between the first row of piles (101) and the second row of piles (102), and the crown beam (202) is used for increasing the rigidity of the structure and restraining the deformation of the pile top; The pile body assembly (100) is arranged in a plum blossom type in an alternating manner; Each single pile in the first row of piles (101) is connected through the crown beam (202), each single pile in the second row of piles (102) is also connected through the crown beam (202), and adjacent single piles in the first row of piles (101) and the second row of piles (102) are alternately connected through the connecting beam (201), so that the pile body assembly (100) forms a better whole.

2. The vibration isolation and bracing periodic row pile structure of claim 1, wherein: The center distance between the first row of piles (101) and the second row of piles (102) is in a reasonable range of 2-5 times the pile diameter.

3. A construction method of periodic row piles with vibration isolation and support, characterized in that: The periodic row pile structure with vibration isolation and support functions comprises the row pile structure with vibration isolation and support functions according to any one of claims 1-2; and Foundation pit dewatering; Foundation pile hole forming; Row pile structure pile hole construction; Crown beam and connecting beam construction; Double-row pile joint wet connection; Foundation pit excavation; Steel mesh hanging between piles and concrete spraying.

4. The method of construction of a periodic row of piles for both vibration isolation and support according to claim 3, characterized in that: The plum blossom type arrangement of the row pile structure improves the pile body density of the row pile barrier system while using the minimum number of piles.

5. The method of construction of a periodic row of piles for both vibration isolation and support according to claim 4, characterized in that: During the crown beam and connecting beam construction, prefabricated reinforced concrete piles and prefabricated composite piles are implanted in the pile holes to form the periodic row pile structure, the crown beam and connecting beam foundation trenches are excavated, and prefabricated reinforced concrete crown beams and prefabricated reinforced concrete connecting beams are implanted.

6. The method of construction of a periodic row of piles for both vibration isolation and support according to claim 5, characterized in that: During the double-row pile joint wet connection, concrete is poured at the joint between the prefabricated reinforced concrete crown beams, the prefabricated reinforced concrete connecting beams and the double-row piles to perform the wet connection.

7. The method for construction of a periodic row of piles for both vibration isolation and support according to claim 6, characterized in that: During the foundation pit excavation, the designed anchor rod positions or support positions are excavated in sequence, the anchor rod or support construction is performed, and when the excavation surface reaches the anchor rod construction working surface, the height difference between the excavation surface and the anchor rod and soil nail should not be greater than 500 mm.

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