阅读说明：本技术 工字型带预应力拉杆及抗推挡墙的双向排桩基础 (H-shaped bidirectional row pile foundation with prestressed pull rod and anti-pushing retaining wall ) 是由 苏恒强 吴泉霖 方虎生 陈志海 林泳 陈银波 欧阳秋 赵安运 李雨盈 梁超群 于 2021-08-19 设计创作，主要内容包括：本发明提供了一种工字型带预应力拉杆及抗推挡墙的双向排桩基础,包括工字型桩承台、挖孔桩、地下连续墙和拉梁,工字型桩承台腹板的上端面连接拱脚,且平行于所述主拱在水平面的投影线方向,翼缘相交于主拱在水平面的投影线方向,挖孔桩等间距分布于工字型桩承台的下端面,与工字型桩承台形成排桩基础,地下连续墙设置在工字型桩承台的下端面,其延伸方向平行于所述工字型桩承台的翼缘,位于工字型桩承台靠近拱轴线末端一侧的翼缘边缘,拉梁采用钢筋混凝土预应力拉梁,通过采用工字型桩承台的腹板结构,能有效抵抗主拱倾斜时所产生的面外方向上的水平荷载,同时避免对靠近拱脚处的路基造成破坏。(The invention provides an I-shaped bidirectional row pile foundation with a prestressed pull rod and an anti-push retaining wall, which comprises an I-shaped pile cap, a bored pile, an underground continuous wall and a pull beam, wherein the upper end surface of a web plate of the I-shaped pile cap is connected with arch legs and is parallel to the projection line direction of a main arch on a horizontal plane, flanges are intersected with the projection line direction of the main arch on the horizontal plane, bored piles are distributed on the lower end surface of the I-shaped pile cap at equal intervals to form a row pile foundation with the I-shaped pile cap, the underground continuous wall is arranged on the lower end surface of the I-shaped pile cap, the extension direction of the underground continuous wall is parallel to the flange of the I-shaped pile cap, the flange edge is positioned on one side of the I-shaped pile cap close to the tail end of an arch axis, the pull beam adopts a reinforced concrete prestressed pull beam, and can effectively resist horizontal load in the out-plane direction generated when the main arch inclines by adopting the main web plate structure of the I-shaped pile cap, meanwhile, the damage to the roadbed close to the arch springing is avoided.)

1. The utility model provides a two-way campshed basis of I-shaped area prestressing force pull rod and anti barricade that pushes away sets up in the arch springing of long-span arch building owner arch, its characterized in that includes:

the upper end surface of the I-shaped pile cap is connected with the arch springing, and the extending direction of the flange of the I-shaped pile cap is intersected with the projection line direction of the main arch on the horizontal plane;

and the hole digging piles are distributed on the lower end face of the I-shaped pile bearing platform at equal intervals and form row pile foundations with the I-shaped pile bearing platform.

2. The I-shaped bidirectional campshed foundation with the prestressed pull rod and the anti-thrust retaining wall as claimed in claim 1, wherein: the underground continuous wall is arranged on the lower end face of the I-shaped pile cap, the extending direction of the underground continuous wall is perpendicular to the projection line direction of the main arch on the horizontal plane, and the underground continuous wall is arranged along the full width of the flange of the I-shaped pile cap.

3. The I-shaped bidirectional campshed foundation with the prestressed pull rod and the anti-thrust retaining wall as claimed in claim 2, wherein: the underground continuous wall is arranged below the I-shaped pile cap and close to the edge of the flange on one side outside the arch springing of the main arch.

4. The I-shaped bidirectional campshed foundation with the prestressed pull rod and the anti-thrust retaining wall as claimed in claim 3, wherein: and a web plate of the I-shaped pile cap is parallel to the projection line direction of the main arch on the horizontal plane.

5. The I-shaped bidirectional campshed foundation with the prestressed pull rod and the anti-thrust retaining wall as claimed in claim 4, wherein: the pile length is 8m to 16 m.

6. The I-shaped bidirectional campshed foundation with the prestressed pull rod and the anti-thrust retaining wall as recited in any one of claims 1 to 5, wherein: the pile length is 10 m.

7. The I-shaped bidirectional campshed foundation with the prestressed pull rod and the anti-thrust retaining wall as recited in claim 6, wherein: and (5) the stirrups within a certain depth range from the pile top are encrypted.

Technical Field

The invention relates to a foundation of a large-span arch building substructure, in particular to a bidirectional row pile foundation.

Background

With the development of building technology and construction technology, large-span structures are increasingly applied to industrial and civil building design. The large-span arch structure is generally applied to roofs and bridge engineering of large-span building engineering, and because the arch is in a curved surface shape, under the action of external force, the bending moment value in the arch can be reduced to the minimum limit, main internal force is changed into axial pressure, the pressure distribution is uniform, the strength of materials can be fully utilized, and the large space can be spanned by the arch structure which is smaller than the beam structure with the same span.

However, the arch structure has a large span and a high height, and the arch foot foundation needs to bear large bidirectional horizontal load, vertical load and rotation bending moment, and in order to bear the load of the structure and maintain the stability of the structure, a wide, thick and firm arch foot foundation must be arranged, so that the difficulty is large in design, for example, in the large-span arch structure of fig. 1, a pair of main arch frames are inclined to the outside by a certain angle, and therefore the foundation at the arch foot needs to bear horizontal load in the plane, such as in the out-of-plane direction, in addition to the vertical load.

In order to bear horizontal load in the in-plane direction of the main arch, the prior art such as the bidirectional cooperative stress long span arch bridge composite pile foundation structure with the publication number of CN207130754U discloses: vertical row piles are arranged in a rock body below the arch support, inclined anti-pushing piles are arranged in the north of the arch support, the front ends of the inclined anti-pushing piles are fixedly combined with the arch support into a whole, the pile bodies of the inclined anti-pushing piles are inclined backwards and downwards to penetrate into the rock body, and the inclined anti-pushing piles and the vertical row piles form a combined pile foundation to resist horizontal loads in the in-plane direction of the arch.

The technical scheme has the following defects:

(1) when the large-span conformal building is applied to a field adjacent to a municipal road, the inclined anti-thrust pile cannot be adopted to avoid damage to a roadbed because the large-span conformal building is surrounded by the municipal road;

(2) the composite pile foundation with the inclined thrust-resisting pile cannot bear horizontal load in the out-of-plane direction.

Disclosure of Invention

The invention aims to provide an I-shaped bidirectional row pile foundation with a prestressed pull rod and an anti-thrust retaining wall, which aims to bear horizontal loads in the inner and outer directions of an arch plane and realize that a large-span arch building can be built in a dense road network.

The utility model provides a two-way campshed basis of I-shaped area prestressing force pull rod and anti barricade that pushes away sets up in the arch springing of long-span arch building owner arch, its characterized in that includes:

the upper end surface of the I-shaped pile cap is connected with the arch springing, and the extending direction of the flange of the I-shaped pile cap is intersected with the projection line direction of the main arch on the horizontal plane;

and the hole digging piles are distributed on the lower end face of the I-shaped pile bearing platform at equal intervals and form row pile foundations with the I-shaped pile bearing platform.

The underground continuous wall is arranged on the lower end face of the I-shaped pile cap, the extending direction of the underground continuous wall is perpendicular to the projection line direction of the main arch on the horizontal plane, and the underground continuous wall is arranged along the full width of the flange of the I-shaped pile cap.

Furthermore, the underground continuous wall is arranged below the I-shaped pile cap and close to the edge of the flange on one outer side of the main arch springing.

Further, a web plate of the I-shaped pile cap is parallel to the projection line direction of the main arch on the horizontal plane.

Compared with the prior art, the invention has the following beneficial effects:

(1) the underground continuous wall is adopted to replace an inclined anti-thrust pile, so that the horizontal load in the inner direction of the main arch is resisted, and meanwhile, the damage to the roadbed close to the arch springing is avoided.

(2) By adopting the web plate structure of the I-shaped pile cap, the horizontal load in the out-of-plane direction generated when the main arch inclines can be effectively resisted.

(3) The flange of the I-shaped pile cap is wide, the lateral rigidity is high, the bending resistance is high, the proportion of the flange is large, the distribution of the cross-sectional area is more reasonable, compared with a square pile cap, under the condition that the sectional area is the same, the strong shaft rigidity is more than 1 time larger than the weak shaft rigidity, the number of I-shaped bidirectional row pile foundation piles is reduced by 18%, and the self weight and the concrete consumption are reduced by 20%.

(4) The pile length of the manual hole digging pile is selected to achieve better engineering economy, after a certain pile length is exceeded, the economic cost is increased more, meanwhile, the stress performance matched with the pile length is not brought, the length of the pile body is adjusted to adapt to bad geological conditions, the pile length is effectively reduced, the self weight of the foundation is reduced, and the consumption of concrete is reduced.

(5) The design method overcomes the defects that the design of horizontal load resistance, vertical load resistance and rotating bending moment resistance is only carried out by independent vertical piles, two underground continuous walls are additionally arranged on the flange of the I-shaped bearing platform, the underground continuous walls, the bearing platform and the manual hole digging pile are fixedly combined into a whole to form a composite pile foundation, and strong horizontal thrust, vertical pressure and rotating bending moment at the end part of the main arch ring are reasonably transmitted to a foundation rock stratum meeting the requirement of bearing capacity.

(6) The underground continuous wall is high in rigidity and horizontal bearing capacity, is effectively combined with the pile cap and the manual hole digging pile, can assist the vertical piles to resist shearing force, axial force and bending moment acting on the arch springing position according to the rigidity of the underground continuous wall, weakens load acting on the vertical piles, and improves rigidity, strength and stability of the row pile foundation.

(7) The capacity of the foundation for resisting the bidirectional horizontal thrust of the arch springing is improved efficiently, the problems that concrete at the top of a pile foundation cracks and steel bars yield due to the fact that part of the pile foundation is easily in a high-shear stress state only by adopting a vertical pile group foundation for an arch bridge with a large horizontal load are solved, and the problem that a traditional inclined thrust-resisting pile is arranged at the back of a bearing platform due to limited site cannot be adopted is also solved.

(8) The material consumption, the excavation volume and the construction difficulty are all smaller than those of the traditional arch foot foundation, the construction difficulty is reduced on the premise of ensuring the structure safety, the construction period is greatly shortened, the construction cost is reduced, and good social benefit and economic benefit are obtained.

Drawings

FIG. 1 is a schematic view of a large span arch supported by the present invention;

FIG. 2 is a side view of a large span arch using the bi-directional pilar foundation of the present invention;

fig. 3 is a plan view of a bidirectional piling base of the arch of fig. 1;

FIG. 4 is a plan view of a single I-shaped pile cap of the bi-directional campshed foundation of the present invention;

FIG. 5 is a side sectional view of a single I-shaped pile cap of the bidirectional campshed foundation according to the present invention;

FIG. 6 is a diagram showing the calculation results of PLAAXIS 3D, a finite element analysis software for Y-direction shearing force of a bored pile according to the first comparative example;

FIG. 7 is a diagram of the calculation results of PLAXIS 3D finite element analysis software for Y-direction shear of a bored pile according to the third embodiment;

FIG. 8 is a graph of the calculation results of PLAXIS 3D, which is finite element analysis software for X-direction shearing force of a bored pile according to comparative example I;

FIG. 9 is a diagram showing the calculation results of PLAXIS 3D, finite element analysis software for X-direction shearing force of a bored pile according to the third embodiment;

wherein: 1, main arch; 2, an I-shaped pile cap; 21 a flange; 22 a web; 3 digging a hole pile; 4 underground continuous wall.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

It should be noted that if directional indications (such as … …, which is up, down, left, right, front, back, top, bottom, inner, outer, vertical, transverse, longitudinal, counterclockwise, clockwise, circumferential, radial, axial) are involved in the embodiment of the present invention, the directional indications are only used for explaining the relative position relationship, motion condition, etc. of the components in a specific posture, and if the specific posture is changed, the directional indications are changed accordingly.

The invention provides an I-shaped bidirectional row pile foundation with a prestressed pull rod and an anti-push retaining wall.

In the embodiment of the present invention, as shown in fig. 2 to 5, the bidirectional campshed foundation includes an i-shaped pile cap 2, a bored pile 3, and an underground diaphragm wall 4.

Specifically, the upper end face of a web plate 22 of an I-shaped pile cap 2 is connected with the arch foot of a main arch 1 and is parallel to the projection line direction of the main arch 1 on the horizontal plane, flange edges 21 are intersected in the projection line direction of the main arch 1 on the horizontal plane, bored piles 3 are distributed on the lower end face of the I-shaped pile cap 2 at equal intervals to form a row pile foundation with the I-shaped pile cap 2, an underground continuous wall 4 is arranged on the lower end face of the I-shaped pile cap 2, the extending direction of the underground continuous wall is parallel to the flange edges 21 of the I-shaped pile cap 2, and the edge of the flange edge 22, which is located on the outer side of the I-shaped pile cap 2 close to the arch foot of the main arch 1, is located to achieve the maximum effect of resisting the linear displacement of the main arch 1.

The beneficial effects of the present invention are demonstrated below by subjecting this embodiment to stress analysis by varying pile lengths and whether or not underground diaphragm wall 4 is erected.

Comparative example 1

The pile foundation is a traditional square bearing platform row pile foundation, the plane size of the square bearing platform is 23200mm in full length and 23200mm in full width, the thickness of the bearing platform is 2500mm, the number of the piles of the manual hole digging pile 3 is 68, and the length of the piles is 15 m.

Example 1

The plane size of the I-shaped pile cap 2 is 23200mm in total length and 23200mm in total width, the width of an upper flange 21 is 8200m, the width of a lower flange 21 is 5200mm, the width of an abdomen is 11200mm, the thickness of the cap is 2500mm, 24 manual hole digging piles 3 are arranged on the upper flange 21 part of the cap, 16 manual hole digging piles 3 are arranged on the lower flange 21 part, 16 manual hole digging piles 3 are arranged on the web 22 part, the total number is 56, and the pile length of the manual hole digging piles 3 is 15 m.

Example 2

The plane size of the I-shaped pile cap 2 is 23200mm in total length and 23200mm in total width, the width of an upper flange 21 is 8200m, the width of a lower flange 21 is 5200mm, the width of an abdomen is 11200mm, the thickness of the cap is 2500mm, 24 manual hole digging piles 3 are arranged on the upper flange 21 part of the cap, 16 manual hole digging piles 3 are arranged on the lower flange 21 part, 16 manual hole digging piles 3 are arranged on the web 22 part, the total number is 56, and the pile length of the manual hole digging piles 3 is 10 m.

Example 3

The plane size of the I-shaped pile cap 2 is 23200mm in total length, 23200mm in full width, 8200m in width of an upper flange 21, 5200mm in width of a lower flange 21, 11200mm in width of an abdomen, 2500mm in thickness of the cap, 24 manual hole digging piles 3 are arranged on the upper flange 21 part of the cap, 16 manual hole digging piles 3 are arranged on the lower flange 21 part, 16 manual hole digging piles 3 are arranged on a web 22 part, the total number is 56, the pile length of the manual hole digging piles 3 is 10m, two underground continuous walls 4 are arranged at the upper flange 21 and the lower flange 21 of the I-shaped pile cap 2 and are perpendicular to the main arch 1 in the horizontal plane projection line direction, the capacity of the foundation for resisting the bidirectional horizontal thrust of the arch feet is improved, the underground continuous walls 4 are arranged along the full width of the flange 21 of the cap of the I-shaped pile cap 2, the thickness is 1200mm, and the height is 4950 mm.

In the first comparative example and examples 1 to 3, the size of the manual bored pile 3 is 1200 × 1200mm, the pile pitch is 3000mm, the characteristic value of the bearing capacity of a single pile is 2000KN, the characteristic value of the horizontal bearing capacity of a single pile is 700KN, the concrete strength grade adopted by the square bearing platform, the i-shaped pile bearing platform 2 and the manual bored pile 3 is C35, and the bottom elevation of the i-shaped pile bearing platform 2 is 0.000 mm.

And the calculation analysis adopts large nonlinear rock-soil finite element analysis software PLAAXIS 3D, the row pile foundation adopts an Embedded pile unit, and a Moore-Coulomb material model simulation soil layer is selected from a constitutive model library to perform stress analysis on the soil layer.

As shown in fig. 3, the main arch 1 of the arch structure has four arch foot foundations, and the foundation of one arch foot is calculated, contrastingly analyzed, so that the inner force of the arch foot of the main arch 1 and the upper load of the i-shaped pile cap 2 are equivalent to the surface load of the i-shaped pile cap 2 as follows:

comparative example one: sigma_x:28.87kN/m²；

σ_y:-48.89kN/m²；

σ_z:-29.36kN/m²；

|σ|:63.92kN/m²；

Examples one to three: sigma_x:36.95kN/m²；

σ_y:-62.57kN/m²；

σ_z:-37.58kN/m²；

|σ|:81.81kN/m²。

The arrangement of each geotechnical layer is as follows:

the displacement table of the I-shaped pile cap 2 obtained by calculation is as follows:

	x direction maximum displacement (mm)	Maximum displacement in Y direction (mm)	Maximum displacement in the Z direction (mm)
				Comparative example 1	6.0701	10.07	56.45
Example one	8.250	11.28	65.91
				Example two	7.613	11.15	80.68
EXAMPLE III	3.571	6.208	65.26

From the above list, it can be seen that after the square pile cap is changed into the i-shaped pile cap 2, the stiffness of the pile cap is not changed much, and after the pile length 15m is changed into 10m, the X-direction displacement of the i-shaped pile cap 2 is reduced to some extent, the Y-direction displacement is basically unchanged, the Z-direction displacement is increased, but the change range is not large, and after the flange 21 is provided with the two underground continuous walls 4, the stiffness of the pile arranging foundation is effectively improved, so that the displacements in all directions are reduced.

The pile bottom axial force table of the manual hole digging cast-in-place pile obtained by calculation is as follows:

	comparative example 1	Example one	Example two	EXAMPLE III
					Maximum axial force of pile body (kN)	3442	3464	2574	2417
Maximum axial force (kN)	1242	1884	1866	1835
					Bottom maximum axial force (kN)	1932	2980	2465	2200

It can be seen from the above list that after the square pile cap is changed into the i-shaped pile cap 2, the axial force of the pile bottom is increased after the number of the manually excavated piles 3 is reduced, and the axial force of the pile bottom is reduced after the pile length is changed from 15m to 10m, and the curve of the axial force of the pile body changing with the depth shows that the position of the maximum axial force of the pile body is not at the pile top but in the middle of the pile. In the row pile foundation under the condition of specific pile spacing and the soil layer characteristics of the site, the soil layer sinking amount is greater than the compression amount of the pile body concrete, so that the soil body generates a pulling force on the pile body, and therefore certain negative frictional resistance is considered in the project, and the bearing capacity of the pile body is rechecked and calculated. When the pile is too long, the negative friction resistance influence section is longer, so that the maximum axial force in the pile with the length of 15 meters is larger than the maximum axial force in the pile with the length of 10 meters; after two underground continuous walls 4 are arranged on the flange 21 of the bearing platform, the load of the upper part of the basement continuous wall is partially shared, and the axial force of the pile bottom is reduced accordingly.

The shear table of the manually excavated cast-in-place pile obtained by calculation is as follows:

as can be seen from the above list, after the square pile cap is changed into the i-shaped pile cap 2, the bidirectional horizontal thrust borne by the manual bored pile 3 has a small variation range; after the length of the pile is changed from 15m to 10m, the length of the pile section mainly bearing shearing force is increased, the shearing force borne by the pile top section is more uniform, so that the bidirectional shearing force of the pile body of the pile with the length of 10m is reduced, and the shearing force curve changing along with the depth shows that under the combined action of pile soil, the manual hole digging pile 3 is subjected to larger shearing force at the pile top, the shearing force is rapidly attenuated along with the increase of the depth, and therefore the stirrups of the pile top are encrypted within a certain depth range. After the pile length exceeds a certain depth, the effect on resisting horizontal shearing force is not great; after the two underground continuous walls 4 are arranged on the flange 21 of the bearing platform, the X-direction horizontal thrust borne by the manual hole digging cast-in-place pile is reduced to a certain extent, but the Y-direction horizontal thrust is obviously reduced.

As shown in fig. 6 to 9, in the third embodiment, after the underground continuous wall 4 is installed, the Y-direction shear force borne by the bored pile 3 is greatly reduced, and the X-direction shear force is only slightly reduced, so that when the wall thickness of the underground continuous wall 4 is parallel to the main arch span direction with a large horizontal acting force, the contact surface between the anti-side member and the soil is increased, and a large shear force is borne.

The displacement table of the artificial dug pile 3 obtained by calculation is as follows:

	x direction maximum displacement (mm)	Maximum displacement in Y direction (mm)	Maximum displacement in the Z direction (mm)
				Comparative example 1	6.147	8.593	55.92
Example one	6.125	9.255	65.13
				Example two	6.523	10.120	80.24
EXAMPLE III	3.414	6.269	65.09

As can be seen from the above list, after the square pile cap is changed into the i-shaped pile cap 2, and the pile length is changed from 15m to 10m, the displacement change in the X direction to the Y direction is not large, the displacement in the Z direction is increased, but the settlement deformation is small, and the rigidity change of the cap is not large; after the flange 21 of the I-shaped bearing platform is provided with the two underground continuous walls 4, the rigidity of the row pile foundation is effectively improved, and the displacement of the manual hole digging pile in the 3X direction and the Y direction is obviously reduced.

The calculated dead weight of the structure and the concrete consumption are as follows:

according to the list, after the square pile bearing platform is changed into the I-shaped bearing platform, the self weight of the structure and the consumption of concrete are reduced by 20 percent; after the pile length is changed from 15m to 10m, the self weight of the structure and the consumption of concrete are reduced by 8 percent compared with the first embodiment; after the two underground continuous walls 4 are arranged on the bearing platform flange 21, the self weight of the structure and the consumption of concrete are increased by 8% compared with the second embodiment, and are reduced by 28% compared with the first embodiment.

In conclusion, compared with the foundation arranged in a square shape, the bidirectional row pile foundation provided by the invention has the advantages that the rigidity change is not large, and two horizontal thrusts with different sizes can be borne well. The foundation of 3 rows of manual hole digging piles with proper pile length can realize better engineering economy, and after a certain pile length is exceeded, the economic cost is increased more, and the stress performance matched with the economic cost is not brought. On the premise of arranging the pile foundation in an I-shaped manner, the flange 21 is additionally provided with the two underground continuous walls 4, so that the horizontal thrust resistance capability of the pile in the direction vertical to the surface of the underground continuous wall 4 can be effectively improved, and the displacement of the manually excavated cast-in-place pile in the X direction and the Y direction is obviously reduced. On the premise of meeting the requirements of standard on vertical bearing capacity, horizontal displacement and settlement deformation of the manual hole digging pile 3, the pile number is effectively reduced, the self weight of the foundation is reduced, and the consumption of concrete is reduced.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.