CN110378013B - Anti-seismic reinforcement design method for phyllostachys pubescens anchor rods in urban wall site containing longitudinal crack rammed earth - Google Patents
Anti-seismic reinforcement design method for phyllostachys pubescens anchor rods in urban wall site containing longitudinal crack rammed earth Download PDFInfo
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Abstract
The invention discloses a method for designing anti-seismic reinforcement of phyllostachys pubescens anchor rods containing longitudinal fracture rammed earth urban wall sites, which is based on the anchoring force demand balance concept, on one hand, the ultimate withdrawal force and anchoring interface mechanical model of the anchor rods under different anchoring parameter combinations are determined through field drawing tests and finite element analysis, and the critical anchoring length is calculated according to the ultimate withdrawal force and anchoring interface mechanical model; on the other hand, the maximum axial drawing load required to be borne by a single anchor rod in a computing unit of the anchoring system under the action of the earthquake and the total anchoring force requirement required for keeping the historic site stable are solved respectively; and finally, determining design parameters such as arrangement distance, quantity and mode of the anchor rods by comparing the relation between the actual total anchoring force provided by the anchoring system and the total anchoring force requirement of the site. By adopting the rammed earth urban wall site phyllostachys pubescens anchor rod anti-seismic reinforcement design method based on anchoring force demand balance, the site anchoring force demand can be met, the secondary damage of reinforcement to the site can be reduced to the greatest extent, and the scientization and refinement of site anchoring are realized.
Description
Technical Field
The invention belongs to the technical field of anchoring rod reinforcement of earthen sites, and particularly relates to a design method for seismic reinforcement of a phyllostachys pubescens anchoring rod containing longitudinal cracks for ramming an earthen wall earthen site.
Background
The existing rammed earth city wall site has the dual attributes of buildings and cultural relics, and under the action of thousands of years of wind and rain erosion and unloading, wide cracks along a longitudinal ramming interface usually exist, and the cracks divide the site into a plurality of high-rise blocks. Under the action of horizontal external force such as earthquake, the cracks gradually expand and penetrate, and the block with small volume is easy to slide, overturn, fall and the like towards the direction of the dead surface of the site. In response to such problems, the cultural relic protection workers usually adopt a concealed reinforcing method of ' full-length bonding type anchoring ' to deal with the problems according to the principles of ' old repair and ' minimum intervention '. The method comprises the steps of utilizing a phyllostachys pubescens anchor rod to tie up a dangerous soil body and a stable soil body on two sides of a crack, namely, drilling a hole into the site from the just empty surface of the dangerous soil body of the site at a certain inclination angle, penetrating the crack to a certain depth in the stable soil body, then implanting the anchor rod in a centering way, injecting an anchoring agent into the anchor hole to bond the anchor rod with the soil body, and finally performing old sealing and protecting treatment on the outer surface of the site. The full-length bonding type anchoring system can uniformly dissipate external seismic load in a soil body through the friction resistance of the anchoring interface, and the aim of enhancing the seismic stability of urban wall sites is fulfilled.
At present, an anchoring design theory and a calculation method aiming at the rammed earth urban wall site do not form a complete system, no relevant standard or standard is available for reference, and an empirical comparison method or an anchoring design theory referring to a traditional soil slope is mostly adopted for making an anchoring scheme.
The empirical comparison method is mainly based on complete and reliable basic engineering data and engineering experience of designers, and simultaneously, the engineering design scheme is adjusted and determined by referring to the anchoring design scheme of similar engineering. The method is simple, convenient and quick, but has high experience dependence on designers, lacks theoretical support and has larger blindness.
The traditional rock-soil side slope anchoring design method mostly takes the prejudgment of a potential slip crack surface as a premise, analyzes the integral stability of the side slope based on a limit balance theory, determines the requirement of total anchoring force, and then carries out anchoring scheme design according to the requirement. The accurate prejudgment of the position and the form of the potential slip surface in the method is the key influencing the rationality of a design result.
However, the damaged forms of the rammed earth urban wall sites are different, and the geographic positions of different sites are greatly different from the environment, so that two similar sites are difficult to find for analog design; in addition, professional knowledge and experience accumulation of different designers are greatly different, and the science and the reasonability of a design scheme are difficult to guarantee.
The traditional anchoring of the rock-soil side slope and the anchoring of a rammed earth city wall site are also greatly different, and the main performance is that (1) the rammed earth city wall site is constructed by artificial rammed earth instead of natural deposition, and a rammed interface or a structurally weak interface generally exists, so that the damage mode of the rammed earth city wall site is mostly cracked and penetrated along the interface under the action of an earthquake and finally overturned and collapsed, and a slip crack surface of the soil side slope is generally penetrated from the top of the slope to the bottom of the slope, and the form of the slip crack surface is more similar to a catenary curve; (2) the historic relics in the ancient site of the city wall are permanently passed through repair, the design service life of the historic relics is longer than that of a modern building, a steel bar anchor rod for traditional slope anchoring is not suitable for anchoring the historic relics in the ancient site due to poor durability, the ancient site is usually reinforced by using an anchor rod made of traditional materials such as phyllostachys pubescens and the like, the strength of an anchoring agent matched with the anchoring agent is lower than that of cement mortar for protecting the safety of the ancient site, and therefore the mechanical behaviors of a phyllostachys pubescens-slurry interface in the ancient site anchoring and a steel bar-cement mortar interface in the slope anchoring are greatly different; (3) in view of the cultural relics property of the urban wall site, the stability problem of the site is essentially solved after the urban wall site is reinforced, secondary damage to the site caused by reinforcement is avoided, and the original appearance of the site cannot be greatly changed, so that the anchoring scheme that a concrete baffle commonly used in the traditional soil slope anchoring is matched with a prestressed anchor rod is limited to use.
In conclusion, the existing anchoring design scheme of the rammed earth urban wall site obtained by adopting an empirical comparison method or referring to a traditional rock-soil slope anchoring method can cause that (1) the anchoring force is insufficient, so that the safety and stability of the urban wall site under the earthquake action cannot be effectively ensured; (2) unnecessary secondary damage to cultural relics in the site is caused by excessive reinforcement, and the minimum intervention principle of cultural relic protection is violated; (3) the excessive adoption of external support causes the original appearance of the site to be greatly changed, and the cultural relic exhibition effect is influenced. Therefore, scientific and reasonable rammed earth urban wall site anchoring design schemes are difficult to obtain by adopting the two design methods.
Analyzing the difference between the traditional soil slope anchoring and the urban wall site anchoring, the anchor rod reinforcing design of the urban wall site has the following problems to be solved urgently:
(1) the interface mechanical behavior of the phyllostachys pubescens anchor rod anchoring system is not clear, so that the distribution form and the transmission rule of the interface stress are difficult to accurately express, and the accurate ultimate pullout resistance and the critical anchoring length cannot be obtained;
(2) the selection basis of the horizontal combination of the anchoring parameters is lacked, and the scientific selection of the anchoring parameters is difficult according to the actual engineering requirements (such as anchoring force requirements, site destruction limits and the like);
(3) there is no systematic and reasonable method for calculating the anchoring force requirement of rammed earth urban wall sites. The method for calculating the anchoring force requirement of the soil slope is not completely suitable for ramming the urban wall site.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention aims to provide a phyllostachys pubescens anchor rod seismic strengthening design method for the urban wall site containing longitudinal crack rammed earth, which can comprehensively reflect the stress performance of an anchoring system, more conveniently obtain the anchoring force requirement of a single anchor rod and the site under the action of an earthquake, and realize scientific, reasonable and efficient urban wall site anchoring design based on the anchoring force requirement balance concept.
The invention is realized by the following technical scheme.
A method for designing anti-seismic reinforcement of phyllostachys pubescens anchor rods in urban sites of rammed earth containing longitudinal cracks comprises the following steps:
(1) determining the ultimate uplift resistance of the phyllostachys pubescens anchoring system in the earthen site and the distribution and transmission rules of interface stress according to a drawing test;
(2) determining a bonding-slipping model representing the mechanical behavior of the anchoring interface;
(3) determining the diameter and anchoring length of an anchor hole by adopting a numerical analysis method according to actual engineering conditions;
(4) respectively calculating the maximum lengths of the elastic section, the softening section and the friction section of the anchoring interface according to a formula and the determined anchoring interface bonding-sliding mechanical model, the diameter of the anchor rod and the diameter of a drilled hole; comparing the calculated critical anchoring length with the anchoring length determined in the step (3), and if the critical anchoring length is smaller than the anchoring length determined in the step (3), determining that the anchoring system can fully exert the anchoring performance;
(5) calculating and analyzing the maximum drawing load required to be borne by a single anchor rod in the range of the calculation unit under the earthquake action;
(6) calculating and analyzing the total anchoring force requirement of the rammed earth urban wall site containing the longitudinal cracks under the action of the earthquake;
(7) calculating an analysis result according to the step (5) and the step (6), calculating the total number of anchor rods required by the site by considering the area of the free surface of the dangerous soil body, and multiplying the algebraic sum of the ultimate anchoring forces of all the anchor rods by a group anchor effect reduction coefficient of 0.85 to obtain the total anchoring force which can be provided by the anchor rods; finally, comparing the total anchoring force provided by the anchor rod with the total anchoring force requirement of the site calculated in the step (6); if the total anchoring force provided by the anchor rod is larger than the total anchoring force requirement of the site, no adjustment is needed; if the total anchoring force is smaller than the total anchoring force requirement of the site, correspondingly reducing the distance between the anchor rods or increasing the number of the anchor rods until the total anchoring force provided by the anchor rods is slightly larger than the total anchoring force requirement of the site;
(8) calculating earthquake safety factors F of the site after anchoring and evaluating the reinforcing effect: when F is equal to 1, the ancient ruined site is in a critical destruction state under the action of the earthquake; when F is greater than 1, the ancient site is in a stable state under the action of the earthquake, and the anchoring scheme does not need to be adjusted; when F is less than 1, the site is still damaged under the action of the earthquake, and the steps (5) - (7) are returned to further modify the anchoring scheme until F is more than 1 or the target safety factor.
Further, in the step (1), a pull-out test is adopted to obtain a load-displacement curve of the loading end of the anchor rod, and the ultimate withdrawal resistance of the anchoring system is judged according to a peak point or a displacement catastrophe point of the load-displacement curve; and analyzing the stress distribution rule of the anchoring interface and the transmission rule of the anchoring interface along with the increase of the load according to the strain monitoring data.
Further, calculating the average shear stress between adjacent strain gauges of the anchoring interface according to strain test data directly obtained by a drawing test; calculating the relative slippage of the anchoring interface according to the distance between adjacent strain measuring points and the strain monitoring data; adopting the shear stress and relative slippage parameters obtained by the calculation to draw an anchoring interface slippage-shear stress curve, comparing the slippage-shear stress curve with the existing bonding-slippage model, and determining the curve form of the anchor rod-slurry interface bonding-slippage mechanical model; and (2) calibrating the slippage and the shear stress value of the key point of the bonding-slippage model according to the corresponding relation between the anchor rod loading end load-displacement curve obtained in the step (1) and the key point of the bonding-slippage model and the inflection point position of the corresponding load-displacement curve, and finally determining the bonding-slippage model.
Further, the step (3) is specifically as follows:
3a) establishing a finite element model of the anchoring system, simulating an anchor rod, slurry and a soil body in the anchoring system by adopting entity units, obtaining a bonding-slippage model by adopting the step (2) for the mechanical behavior of the anchor rod and the slurry interface, and simulating by adopting a nonlinear spring unit;
3b) the finite element model is adopted to analyze the ultimate pullout resistance and the drilling hole damage amount of the anchoring system under different anchor hole diameters and anchoring depth parameter combinations respectively, and comprehensively determine the anchor rod diameter, the drilling hole diameter and the anchoring depth parameter according to the requirements on anchoring force, site destructive construction limitation and the like in actual engineering.
Further, the step (5) analyzes and calculates the maximum drawing load required to be borne by a single anchor rod within the unit range, and specifically comprises the following steps:
5a) presetting longitudinal and transverse intervals of anchor rods according to experience, and calculating the maximum drawing load of a single anchor rod containing a longitudinal fissure earthen site in a calculation unit under the target fortification earthquake intensity;
5b) comparing the calculated maximum drawing load required to be borne by the single anchor rod with the limit uplift force of the single anchor rod; if the value is 80-90% of the ultimate withdrawal resistance, the adjustment is not needed; if the value exceeds 90% of the limit withdrawal resistance, correspondingly reducing the distance between the anchor rods, and returning to the step 5(a) for trial calculation again; and if the value is less than 80% of the limit withdrawal resistance, the distance between the anchor rods is increased moderately, and the step 5(a) is returned for trial calculation again.
Further, the maximum drawing load required to be borne by the single anchor rod calculated according to the reduced anchor rod spacing is not more than 90% of the ultimate withdrawal resistance of the single anchor rod, and the longitudinal and transverse spacing of the reduced anchor rod is not less than 0.6 m;
the maximum drawing load required to be borne by the single anchor rod calculated according to the increased distance between the anchor rods is not more than 90% of the ultimate pullout resistance of the single anchor rod, and the longitudinal and transverse distances between the increased anchor rods are not more than 2.5 m.
Further, the step (6) of calculating and analyzing the total anchoring force requirement of the rammed earth urban area site containing the longitudinal cracks under the earthquake action is as follows: the method comprises the steps of preliminarily judging the position and the damage mode of a potential cracking section when a dangerous soil body is damaged under the action of an earthquake according to the crack position, the damage form and the boundary constraint condition of a rammed earth urban wall site, analyzing the critical horizontal earthquake acceleration causing interface cracking, then calculating the accumulated expansion depth of the potential cracking section under the action of the earthquake, judging whether the site is damaged under the action of the earthquake, limiting the first cracking expansion depth of the potential cracking section to be zero, and calculating the total anchoring force requirement of the site.
Further, calculating the critical horizontal seismic acceleration for cracking the section and the cracking depth of the section at the bottom of the dangerous soil body when the critical horizontal seismic acceleration is exceeded each time in the step (6); algebraically adding the cracking depths of each time to obtain the total cracking depth of the section in the whole process of the earthquake action, then comparing the residual effective height of the section with the residual effective height of the critical section, and if the former is larger than the latter, the site cannot be overturned and damaged; if the former is equal to the latter, the site is in the critical state of overturning damage; if the former is smaller than the latter, the site will be overturned and destroyed.
Due to the adoption of the technical scheme, the invention has the following beneficial effects:
based on the anchoring force demand balance concept, a systematic, scientific and reasonable method for seismic reinforcement design of phyllostachys pubescens anchor rods containing longitudinal cracks and rammed earth in urban wall sites is provided, the method can meet the anchoring force demand of sites under the action of earthquakes, can effectively limit damage of excessive reinforcement to the cultural relics in the sites, and achieves good balance of anchoring force and damage to the sites. The method has the characteristics of clear concept, convenience in calculation, higher precision and the like, and facilitates engineering technicians to design the anchoring scheme according to the actual site anchoring engineering requirements.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention:
FIG. 1 is a schematic view of the consolidation of a phyllostachys pubescens anchor rod containing longitudinal cracks in a rammed earth wall site;
FIG. 2 is a flow chart of an anchor design method;
fig. 3 is a drawing test schematic diagram of a single phyllostachys pubescens anchor rod anchoring system;
fig. 4(a) and (b) are corresponding diagrams of a load-displacement curve of a loading end of a phyllostachys pubescens anchor rod and a phyllostachys pubescens-slurry interface bonding-slippage mechanical model respectively;
FIGS. 5(a) and (b) are respectively value-taking graphs of ultimate withdrawal resistance and site destruction of the anchoring system under different anchor hole diameter and anchoring depth parameter combinations obtained by finite element analysis;
FIG. 6 is the adjusted EL-Centro seismic waves according to the 7-degree seismic fortification target;
FIG. 7 is a graph of horizontal seismic waves versus critical seismic acceleration for cross-sectional cracking;
FIG. 8(a) is a front view of a section of the anchor rod arrangement blank surface of a rammed earth city wall obtained by the method of the present invention; FIG. 8(b) is a side perspective view of a section of bolt reinforcement of a rammed earth urban wall obtained by the method of the present invention.
In the figure: 1. ramming a dead site of a wall; 2. a hazardous soil mass; 3. stabilizing the soil mass; 4. longitudinal fractures; 5. a potential crack section; 6. anchoring the slurry; 7. a phyllostachys pubescens anchor rod; 8. calculating a unit range; 7-1, phyllostachys pubescens wall; 7-2, loading a steel bar; 7-3, a first bamboo joint; 7-4, epoxy resin glue; 7-5, wood base plate; 7-6, a reaction frame; 7-7, a displacement meter; 7-8, clamping; 7-9, drawing loader; 7-10 and strain gauges.
Detailed Description
The invention will be described in detail with reference to the drawings and specific embodiments, which are provided herein for the purpose of illustrating the invention and are not to be construed as limiting the invention.
As shown in fig. 1, the schematic diagram of phyllostachys pubescens anchor rod reinforcement of the urban wall site of the rammed earth containing longitudinal cracks is shown, the total height H of a wall body of a certain section of the wall of the Gaichang city in Xinjiang province is about 12.7m, the thickness of the wall top is about 8.2m, the included angle between the wall surface and the ground is about 80 degrees, the cracks develop from top to bottom along the longitudinal ramming interface, the cracked depth is about 5.8m, the soil body on the side, facing the air, of the wall is divided into high-rise vertical blocks, and the geometric dimension of the blocks is 8.7m (height) multiplied by 4.6m (width) multiplied by 1.7m (thickness).
The technical scheme includes that a longitudinal crack 4 developing along a longitudinal ramming interface is formed in the upper portion of a rammed earth urban site 1, the rammed earth urban site 1 is divided into a left dangerous soil body 2 and a right stable soil body 3, a potential cracking cross section 5 exists at the bottom of the dangerous soil body 2, a plurality of phyllostachys pubescens anchor rods 7 are installed in the dangerous soil body 2, the longitudinal crack 4 and the stable soil body 3 to form an anchoring system, each anchoring system uses an anchor rod as a center to define a calculation unit range 8, anchoring slurry 6 is injected into the periphery of each phyllostachys pubescens anchor rod 7, and the left dangerous soil body 2 and the right stable soil body 3 of the longitudinal crack 4 are tied.
The physical and mechanical properties of the undisturbed ruined rammed soil body are measured by an indoor test and are shown in the table 1.
TABLE 1 original site soil physical and mechanical properties
As shown in fig. 2, the anchoring scheme design for the wall body by using the anchoring design method of the present invention includes the following specific steps:
(1) and (4) determining the ultimate uplift resistance of the phyllostachys pubescens anchoring system in the earthen site and the distribution and transmission rule of interface stress by adopting a drawing test.
The drawing test device shown in the attached drawing 3 is adopted and comprises an anchor rod, a soil body, anchoring slurry and the like, wherein the anchor rod comprises a plurality of bamboo joints, a loading reinforcing steel bar 7-2 is arranged in the first opened bamboo joint 7-3, epoxy resin glue 7-4 is poured into the loading reinforcing steel bar, and the anchoring slurry 6 is poured on the periphery of the phyllostachys pubescens wall 7-1; the method is characterized in that strain gauges 7-10 are pasted on the interface of an anchor rod and anchor slurry 6 at equal intervals, a wooden base plate 7-5 is arranged on the surface of rammed earth at an anchor hole, a reaction frame 7-6 is mounted on the wooden base plate, a displacement meter 7-7 is fixed on the reaction frame 7-6, a loading steel bar 7-2 is connected with a clamp 7-8, and a drawing loader 7-9 is arranged at the front end of the clamp 7-8.
Axial drawing loads are applied to the anchor rod through the drawing loader 7-9, a relation curve of the loads and displacement of a loading end of the anchor rod is synchronously recorded, and distribution and an evolution rule of stress of an anchoring interface in the loading process are analyzed. And judging that the ultimate pullout resistance of the anchoring system is about 40.5kN according to the peak point or the displacement catastrophe point of the load-displacement curve of the anchor rod loading end. According to the stress distribution rule of the anchoring interface and the transmission rule of the anchoring interface along with the increase of the load, the stress distribution rule of the anchoring interface and the monitoring data of the strain gauge 7-10 are analyzed, and the obvious non-uniform distribution characteristic of the interface shear stress exists, the stress value near the loading end is large, and the shear stress peak value is gradually transferred to the anchoring end along with the increase of the load.
(2) Determining a bond-slip model characterizing mechanical behavior of an anchoring interface
According to the strain test data directly obtained by the drawing test, the average shear stress between adjacent strain gauges of the anchoring interface can be calculated according to the following formula:
wherein: e p And r p Respectively the axial rigidity and the radius of the anchor rod; epsilon i And ε i+1 Strain values measured for the ith and (i + 1) th strain gauges, respectively; x is the number of i+1 -x i Is the distance between adjacent strain gauges; τ (x) is the average shear stress between adjacent strain gages;
according to the distance between adjacent strain measuring points and the strain monitoring data, the relative slippage of the anchoring interface can be calculated by the following formula:
wherein: x is the distance between the anchoring interface relative slippage calculation point and the anchoring end;
and (3) drawing an anchoring interface slippage-shear stress curve by adopting the shear stress and relative slippage parameters obtained by the calculation, comparing the anchoring interface slippage-shear stress curve with the existing bonding-slippage model according to the attached drawings 4(a) and (b), determining the curve form of the anchor rod-slurry interface bonding-slippage mechanical model, calibrating the slippage and the shear stress value of the key point of the bonding-slippage model according to the corresponding relation between the anchor rod loading end load-displacement curve obtained in the step (1) and the key point of the bonding-slippage model, and finally determining the bonding-slippage model.
In this example, the slippage and the shear stress at the key point A, B, C (points i, ii, and iii correspond to points A, B, C, respectively) corresponding to the adhesion-slippage model are determined according to the position coordinates of inflection points i, ii, and iii of the load-displacement curve, and the obtained curve is shown in fig. 4(b) and corresponds to the parameter s 1 ＝3.34mm，s 2 ＝10.73mm，s 3 ＝22.56mm，τ 1 ＝1.89MPa，τ 2 ＝0.44MPa。
(3) Determining the diameter and anchoring depth of the anchor hole by adopting a numerical analysis method according to actual engineering conditions
3a) And (3) establishing a finite element model of the anchoring system by adopting large-scale general finite element software ANSYS, simulating the anchor rod, the slurry and the soil body by adopting entity units SOLID186, and simulating the mechanical behavior of the interface of the anchor rod and the slurry by adopting a nonlinear spring unit according to the bonding-sliding model obtained in the step (2). The finite element model is adopted to analyze the ultimate pullout resistance and the drilling failure amount of the anchoring system under different anchor hole diameter and anchoring depth parameter combinations respectively, and the results are shown in the attached figures 5(a) and (b).
3b) The larger the anchoring force is, the better the site destruction is, the smaller the site destruction is, and the distance between the bottom end of the drilling hole and the opposite side face of the blank is greater than 1/4 wall bottom thickness, according to the above conditions and the numerical simulation results shown in the attached figures 5(a) and 5(b), the diameter of the anchor rod is 35mm, the diameter of the anchor hole is 95mm, the anchoring depth is 3.2m, the corresponding ultimate pullout resistance of the anchor rod is 43kN (which is closer to the experimental value of 40.5kN), and the destruction of the drilling hole is 0.061m 3 。
(4) Calculating the critical anchoring length of the anchoring system
Calculating the critical anchoring length by adopting the diameter of the anchoring hole determined in the step (3) to be about 95 mm; the diameter of the phyllostachys pubescens anchor rod is about 35mm, and the elastic modulus is about 6.6 GPa; the shear modulus of the anchoring slurry is 35.17 MPa. Calculating the maximum lengths of the elastic section, the softening section and the friction section of the anchor rod according to the data:
In the formula: s is 1 、s 2 、s 3 The maximum slippage, tau, of the anchoring interface at the tail loading end of the elastic section, the softening section and the friction section respectively 1 、τ 2 Maximum shear stress at the interface corresponding to the elastic section and the soft section end, respectively, E p For axial stiffness of the anchor rod, r p Radius of anchor rod, G c To anchor the shear stiffness of the slurry, r t Is the anchor eye radius, and P is the axial pull load.
And is
In the formula, alpha 1 、α 2 、α 3 Respectively an elastic segment length calculation variable, a softening segment length calculation variable and a friction segment length calculation variable;
the algebraic sum of the maximum length of the elastic section, the maximum length of the softening section and the maximum length of the friction section of the anchoring interface is the critical anchoring length of the anchoring system, and can be calculated according to the following formula:
Is calculated to obtain
Critical anchoring length L of anchoring system eff 0.946m +0.674m + 0.5. And (4) comparing the anchoring length of 3.2m determined in the step (3), wherein the value of the anchoring length is greater than the critical anchoring length of 2.2m, so that the performance of the anchoring system can be fully exerted, and the anchoring length is taken to be 3.2m for safety.
(5) Calculating and analyzing the maximum pulling load required to be borne by a single anchor rod under the action of earthquake
5a) Aiming at 7-degree seismic fortification, the peak acceleration of the EL-Centro seismic wave is adjusted to be 0.15g, and the frequency is 2Hz, as shown in figure 6. Firstly, presetting that the longitudinal and transverse distances of anchor rods are all 1.2m, the anchoring inclination angle is 10 degrees, and calculating the maximum drawing load required to be born by a single anchor rod according to the following formula:
in the formula:
and:
k f ＝δE f ，η f ＝2ρ f W(V s1 +V p1 )
wherein: E. a, D are the rigidity, sectional area and section perimeter of the anchor rod; theta is an anchoring inclination angle; y, Q are respectively a drawing load calculation variable and an adjustment variable; f 1 ～F 6 Respectively calculating variables 1-6 for undetermined coefficients; l is a To stabilize the anchoring length in the earth; u shape g And omegaAmplitude and frequency of horizontal vibration, respectively; e f The compression modulus of the soil body of the site; rho f The density of the soil body of the site is shown; v s1 、V p1 Respectively the shear wave velocity and the compression wave velocity of the soil body of the site; w is the calculated width, and the sum of the distances between the calculated anchor rod and the middle points of the adjacent anchor rods on the two sides is taken; k is a radical of l The equivalent spring stiffness of the fracture section anchor rod under the drawknot effect can be measured through tests; m is the weight of a calculation unit of the dangerous soil body; and delta is a correction coefficient of the friction resistance of the soil body to the anchor rod, and is 1.5-1.6.
The maximum drawing load required to be borne by the anchor rod at the first row of the historical site is N fmax ＝1.6N f Wherein 1.6 is the seismic acceleration amplification coefficient of the top of the site at the anchor rod of the first row.
5b) Calculating the maximum drawing load N required to be borne by a single anchor rod fmax The tensile strength is only 25.37kN and is less than 80 percent of the ultimate pullout resistance (40.5kN) of the anchoring system, the performance of the anchoring system cannot be fully exerted, so that the longitudinal and transverse spacing of the anchor rods can be properly increased, and the calculation can be carried out again according to the step (5) until the maximum pullout load N required to be borne by a single anchor rod is reached fmax Between 80% and 90% of the ultimate pullout resistance of the anchoring system. The maximum drawing load required to be borne by a single anchor rod calculated according to the reduced anchor rod spacing is not more than 90% of the ultimate pullout resistance of the single anchor rod, and the longitudinal and transverse spacing of the reduced anchor rod is not less than 0.6 m; the maximum drawing load required to be born by a single anchor rod calculated according to the increased distance between the anchor rods is not more than 90% of the ultimate withdrawal resistance of the single anchor rod, and the longitudinal and transverse distances between the anchor rods are not more than 2.5 m.
In one embodiment, after trial calculation, the maximum drawing load required to be borne by a single anchor rod when the transverse spacing of the anchor rods is 1.2m and the longitudinal spacing of the anchor rods is 1.5m can be finally determined to be 36.09kN which is about 89.1 percent of the ultimate withdrawal resistance (40.5kN), so that the spacing of the anchor rods and the maximum drawing load required to be borne by the anchor rods can meet the requirements.
(6) Calculating and analyzing total anchoring force requirement of longitudinal crack-containing site under earthquake action
According to the attached figure 8(b), the longitudinal cracks of the urban wall site divide the site into a dangerous soil body and a stable soil body, and the dangerous soil body is toweringThe bottom section of the vertical section is a potential cracking section, and the residual effective height h of the critical section of the section is equal to the residual effective height h when the dangerous body is subjected to overturning damage cri And (0), namely the bottom section of the dangerous soil body is completely cracked and penetrated.
According to the local seismic fortification intensity of 6 degrees, the national key cultural relic protection unit needs to improve the fortification intensity by one level, the seismic fortification intensity of the site is set to be 7 degrees, and the horizontal seismic acceleration peak value is 0.15 g.
a. Calculating the critical horizontal seismic acceleration that cracks the section
Each time the seismic wave horizontal acceleration exceeds the critical horizontal seismic acceleration, the fracture propagation of the cross section occurs, and the relationship between the two is shown in fig. 7.
b. Calculating the cracking depth of the bottom section of the dangerous soil body when the seismic acceleration exceeds the critical level each time, and calculating the cracking depth of the bottom section of the dangerous soil body when the seismic acceleration exceeds the critical level each time according to the following formula:
algebraically adding the cracking depths of each time to obtain the total cracking depth of the section in the whole process of the earthquake action, then comparing the residual effective height of the section with the residual effective height of the critical section, and if the former is larger than the latter, the site cannot be overturned and damaged; if the former is equal to the latter, the site is in the critical state of overturning damage; if the former is smaller than the latter, the site will be overturned and destroyed.
c. Aiming at limiting the first cracking of a potential cracking section (namely enabling the bottom section of a dangerous body to crack and expand the depth h under the action of earthquake 0 ' -0), calculating the siteTotal anchorage force requirement T u 。
Total anchorage force requirement T of site under earthquake action u Can be calculated from the following formula:
wherein: sigma t ' is the rammed earth tensile strength; h is 0 An initial fracture depth for the potential fracture section; m is the weight of the dangerous soil body; e is the elastic modulus of the rammed earth body; delta (t) is a horizontal seismic acceleration subentry coefficient; t is u (t) the total anchoring force requirement of the site at the time t, and the value of the total anchoring force requirement before anchoring is 0; theta is an anchoring inclination angle; h 2 The height of a longitudinal connecting section of the dangerous soil body and the stable soil body is set; l, b and h are respectively the total height, the calculated width and the calculated depth of the dangerous soil body; tau. u Shearing force is applied to a longitudinal connecting interface of a dangerous soil body and a stable soil body; w 1 Projecting the gravity center of the dangerous soil body to the horizontal distance of the empty face; w is a group of 2 Calculating the depth of the potential cracking section of the dangerous soil body; Ψ is the energy at break required for the cracking per unit area of the cross section, and can be determined by experimentation.
The calculation result of the example shows that the critical horizontal seismic acceleration alpha required by the cracking of the bottom section of the dangerous soil body k (t)＝1.25m/s 2 Comparing the wave time curve of the EL-Centro wave, the seismic acceleration is 0.15g when t is 2.22s, the corresponding crack propagation depth is 0.112m when the t exceeds the critical horizontal seismic acceleration, and the seismic acceleration does not exceed the critical horizontal seismic acceleration after the t exceeds the critical horizontal seismic acceleration, so that the crack propagation of the section cannot be continued. The effective residual section height of the bottom potential cracking section is 1.59m by calculation>h cri 0m, so that the dangerous body can not be overturned and damaged, but the bottom section can be cracked and expanded once. The total anchorage force requirement T of the site can be calculated by taking the limitation of the first cracking of the dangerous section as a target u ＝320.96kN。
(7) Comprehensively considering the calculation and analysis results of the step (5) and the step (6), correcting and optimizing the anchoring design scheme
a. According to the calculation result of the anchor rod spacing in the step (5), the longitudinal and transverse spacing is respectively 1.5m,1.2m, considering that the size of the free face of the dangerous object is 8.7m (height) × 4.6m (width), the total number of anchor rods required for primarily estimating the site is 13, and the anchor rods are arranged in a quincunx shape with 5 rows from top to bottom, as shown in fig. 8(a), the total anchoring force provided by all the anchor rods is 13 × 40.5kN which is 526.5kN, considering that the reduction coefficient of the group anchor effect is 0.85, and the actual total anchoring force T provided by all the anchor rods can be obtained s The value was 526.5kN × 0.85 ═ 447.53 kN.
b. And (4) comparing the actual total anchoring force provided by all the anchor rods with the total anchoring force requirement of the site calculated in the step (6), so that the actual total anchoring force 447.53kN provided by all the anchor rods is greater than the total anchoring force requirement of the site 320.96kN, and therefore, adjustment and optimization are not needed.
(8) Calculating the safety coefficient of the site after anchoring and evaluating the reinforcing effect
Calculating the site safety factor F (the actual total anchoring force T provided by all anchor rods) s And site total anchoring force requirement T u Ratio of).
In the embodiment, the destination safety factor of the site is set to be 1.3, the site safety factor F is calculated to be 447.53/320.69 which is 1.39 and is more than 1.3, the site is in a stable state under the action of an earthquake, the bottom section of a dangerous soil body cannot crack, the requirement of anchoring force can be met, and the anchoring scheme is reasonable.
Thus, the design scheme of the rammed earth urban wall site anchoring containing the longitudinal cracks in the embodiment can be obtained (see the attached figures 8(a) and (b)):
the diameter of the phyllostachys pubescens anchor rods is 35mm, the diameter of the drilled hole is 95mm, the anchoring depth in the stabilizing body is 3.2m, the transverse distance between every two anchor rods is 1.2m, the longitudinal distance is 1.5m, the anchoring angle is 10 degrees, and the phyllostachys pubescens anchor rods are arranged in a quincunx manner. The safety factor of the anchored site under the action of a horizontal earthquake is 1.39.
The present invention is not limited to the above embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts based on the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.
Claims (10)
1. A method for designing the anti-seismic reinforcement of phyllostachys pubescens anchor rods in urban sites of rammed earth containing longitudinal cracks is characterized by comprising the following steps:
(1) determining the ultimate uplift resistance of the phyllostachys pubescens anchoring system in the earthen site and the distribution and transmission rules of interface stress according to a drawing test;
(2) determining a bonding-slipping model representing the mechanical behavior of the anchoring interface;
(3) determining the diameter and anchoring length of an anchor hole by adopting a numerical analysis method according to actual engineering conditions;
(4) respectively calculating the maximum lengths of the elastic section, the softening section and the friction section of the anchoring interface according to a formula and the determined anchoring interface bonding-sliding mechanical model, the diameter of the anchor rod and the diameter of a drilled hole; comparing the calculated critical anchoring length with the anchoring length determined in the step (3), and if the critical anchoring length is smaller than the anchoring length determined in the step (3), determining that the anchoring system can fully exert the anchoring performance;
(5) calculating and analyzing the maximum drawing load required to be borne by a single anchor rod in the range of the calculation unit under the action of the earthquake;
(6) calculating and analyzing the total anchoring force requirement of the rammed earth urban wall site containing the longitudinal cracks under the action of the earthquake;
(7) calculating an analysis result according to the step (5) and the step (6), calculating the total number of anchor rods required by the site by considering the area of the free surface of the dangerous soil body, and multiplying the algebraic sum of the ultimate anchoring forces of all the anchor rods by a group anchor effect reduction coefficient of 0.85 to obtain the total anchoring force which can be provided by the anchor rods; finally, comparing the total anchoring force provided by the anchor rod with the total anchoring force requirement of the site calculated in the step (6); if the total anchoring force provided by the anchor rod is larger than the total anchoring force requirement of the site, no adjustment is needed; if the total anchoring force requirement of the site is less than the total anchoring force requirement of the site, correspondingly reducing the distance between the anchor rods or increasing the number of the anchor rods until the total anchoring force provided by the anchor rods is slightly greater than the total anchoring force requirement of the site;
(8) calculating earthquake safety factors F of the site after anchoring and evaluating the reinforcing effect: when F is equal to 1, the ancient ruined site is in a critical destruction state under the action of the earthquake; when F is greater than 1, the ancient site is in a stable state under the action of the earthquake, and the anchoring scheme does not need to be adjusted; when F is less than 1, the site is still damaged under the action of the earthquake, and the steps (5) - (7) are returned to further modify the anchoring scheme until F is more than 1 or the target safety factor.
2. The method for designing the phyllostachys pubescens anchor rod seismic reinforcement containing the longitudinal crack rammed earth urban wall site according to claim 1, wherein in the step (1), a load-displacement curve of a loading end of the anchor rod is obtained by adopting a drawing test, and the ultimate withdrawal resistance of an anchoring system is judged according to a peak point or a displacement mutation point of the load-displacement curve; and analyzing the stress distribution rule of the anchoring interface and the transmission rule of the anchoring interface along with the increase of the load according to the strain monitoring data.
3. The method for designing the phyllostachys pubescens anchor rod seismic reinforcement containing the longitudinal crack rammed earth urban wall site according to claim 1, wherein the average shear stress between adjacent strain gauges of an anchoring interface can be calculated according to strain test data directly obtained by a drawing test by the following formula:
wherein: e p And r p Respectively the axial rigidity and the radius of the anchor rod; epsilon i And ε i+1 Strain values measured for the ith and (i + 1) th strain gauges, respectively; x is the number of i+1 -x i Is the distance between adjacent strain gauges; τ (x) is the average shear stress between adjacent strain gages;
according to the distance between adjacent strain measuring points and the strain monitoring data, the relative slippage of the anchoring interface can be calculated by the following formula:
wherein: x is the distance between the anchor interface relative slippage calculation point and the anchor end;
adopting the shear stress and relative slip parameter obtained by the calculation to draw an anchoring interface slip-shear stress curve, comparing the slip-shear stress curve with the existing bonding-slip model, and determining the curve form of the anchor rod-slurry interface bonding-slip mechanical model; and (2) calibrating the slippage and the shear stress value of the key point of the bonding-slippage model according to the corresponding relation between the anchor rod loading end load-displacement curve obtained in the step (1) and the key point of the bonding-slippage model and the inflection point position of the corresponding load-displacement curve, and finally determining the bonding-slippage model.
4. The method for designing the phyllostachys pubescens anchor rod seismic reinforcement containing the longitudinal crack rammed earth urban wall site according to claim 1, wherein the step (3) is specifically as follows:
3a) establishing a finite element model of the anchoring system, simulating an anchor rod, slurry and a soil body in the anchoring system by adopting entity units, obtaining a bonding-slippage model by adopting the step (2) for the mechanical behavior of the anchor rod and the slurry interface, and simulating by adopting a nonlinear spring unit;
3b) the finite element model is adopted to analyze the ultimate pullout resistance and the drilling failure amount of the anchoring system under different anchor hole diameters and anchoring depth parameter combinations respectively, and the anchor rod diameter, the drilling diameter and the anchoring depth parameter are determined comprehensively according to the destructive construction limiting requirements on the anchoring force and the site in the actual engineering.
5. The method for designing the phyllostachys pubescens anchor rod seismic reinforcement containing the longitudinal crack rammed earth urban wall site according to claim 1, wherein the maximum length formula of the elastic section, the softening section and the friction section of the anchoring interface calculated in the step (4) is as follows:
maximum length of elastic section of anchoring interface:
maximum length of softening section:
maximum length of friction segment:
in the formula: s 1 、s 2 、s 3 The maximum slippage, tau, of the anchoring interface at the loading end of the elastic section, the softening section and the friction section respectively 1 、τ 2 Maximum shear stress at the interface corresponding to the elastic section and the soft section respectively, E p For axial stiffness of the anchor rod, r p Radius of anchor rod, G c To anchor the shear stiffness of the slurry, r t Is the anchor hole radius, and P is the axial drawing load;
and is
In the formula, alpha 1 、α 2 、α 3 Respectively calculating variables for the length of the elastic segment, the length of the softened segment and the length of the friction segment;
the algebraic sum of the maximum length of the elastic segment, the maximum length of the softening segment and the maximum length of the friction segment of the anchoring interface is the critical anchoring length L of the anchoring system eff ：
6. The method for designing the phyllostachys pubescens anchor rod seismic reinforcement containing the longitudinal crack rammed earth urban wall site according to claim 1, wherein the step (5) is used for analyzing and calculating the maximum pulling load required to be borne by a single anchor rod in a unit range, and specifically comprises the following steps:
5a) the longitudinal and transverse distances of the anchor rods are preset according to experience, the maximum drawing load of a single anchor rod containing a longitudinal fissure earthen site in a calculation unit under the target fortification seismic intensity is calculated, and the calculation can be carried out according to the following formula:
in the formula:
and:
k f ＝δE f ，η f ＝2ρ f W(V s1 +V p1 )
wherein: E. a, D are the rigidity, sectional area and section perimeter of the anchor rod; theta is an anchoring inclination angle; y, Q are respectively a drawing load calculation variable and an adjustment variable; f 1 ～F 6 Respectively calculating variables 1-6 for undetermined coefficients; l is a To stabilize the anchoring length in the earth; u shape g And ω is the amplitude and frequency of the horizontal vibration, respectively; e f The compression modulus of the soil body of the site; rho f Is the site of the ancient ruinedDensity of soil mass; v s1 、V p1 Respectively the shear wave velocity and the compression wave velocity of the soil body of the site; w is the calculated width, and the sum of the distances between the calculated anchor rod and the middle points of the adjacent anchor rods on the two sides is taken; k is a radical of l The equivalent spring stiffness of the fracture section anchor rod under the drawknot effect can be measured through tests; m is the weight of a dangerous soil body calculation unit; delta is a correction coefficient of the friction resistance of the soil body to the anchor rod;
5b) comparing the calculated maximum drawing load required to be borne by the single anchor rod with the limit uplift resistance of the single anchor rod; if the value is 80-90% of the ultimate withdrawal resistance, the adjustment is not needed; if the value exceeds 90% of the limit withdrawal resistance, correspondingly reducing the distance between the anchor rods, and returning to the step 5(a) for trial calculation again; and if the value is less than 80% of the limit withdrawal resistance, the distance between the anchor rods is increased moderately, and the step 5(a) is returned for trial calculation again.
7. The method for designing the phyllostachys pubescens anchor rod seismic reinforcement containing the longitudinal crack rammed earth urban wall site according to claim 6, wherein the maximum drawing load required to be borne by a single anchor rod obtained by calculating according to the reduced anchor rod spacing is not more than 90% of the ultimate withdrawal resistance of the single anchor rod, and the longitudinal and transverse spacing of the reduced anchor rod is not less than 0.6 m;
the maximum drawing load required to be borne by the single anchor rod calculated according to the increased distance between the anchor rods is not more than 90% of the ultimate pullout resistance of the single anchor rod, and the longitudinal and transverse distances between the increased anchor rods are not more than 2.5 m.
8. The method for designing the phyllostachys pubescens anchor rod seismic reinforcement of the urban site containing the longitudinal fracture rammed earth as claimed in claim 1, wherein the step (6) is used for calculating and analyzing the requirement of the total anchoring force of the urban site containing the longitudinal fracture rammed earth under the action of an earthquake, and specifically comprises the following steps:
the method comprises the steps of preliminarily judging the position and the damage mode of a potential cracking section when a dangerous soil body is damaged under the action of an earthquake according to the crack position, the damage form and the boundary constraint condition of a rammed earth urban wall site, analyzing the critical horizontal earthquake acceleration causing interface cracking, then calculating the accumulated expansion depth of the potential cracking section under the action of the earthquake, judging whether the site is damaged under the action of the earthquake, limiting the first cracking expansion depth of the potential cracking section to be zero, and calculating the total anchoring force requirement of the site.
9. The method for designing the phyllostachys pubescens anchor rod seismic reinforcement containing the longitudinal crack rammed earth urban wall site according to claim 8, wherein in the step (6):
calculating the critical horizontal seismic acceleration that cracks the section:
when the horizontal acceleration of seismic waves exceeds the critical horizontal seismic acceleration, the section can crack and expand once;
calculating the cracking depth of the bottom section of the dangerous soil body when the earthquake acceleration exceeds the critical horizontal acceleration at each time:
adding the algebraic numbers of the cracking depths of each time to obtain the total cracking depth of the section in the whole process of the seismic action, then comparing the residual effective height of the section with the residual effective height of the critical section, and if the former is greater than the latter, the site cannot be overturned and damaged; if the former is equal to the latter, the site is in the critical state of overturning damage; if the former is smaller than the latter, the site will be overturned and destroyed;
the crack expansion depth h of the bottom section of the dangerous body under the action of earthquake 0 ' 0, calculating the total anchoring force requirement T of the site according to the following formula u ：
In the formula: sigma t ' is the rammed earth tensile strength; h is 0 To potential crackingInitial cracking depth of the section; m is the weight of the dangerous soil body; e is the elastic modulus of the rammed earth body; delta (t) is a horizontal seismic acceleration subentry coefficient; t is u (t) the total anchoring force requirement of the site at the time t, and the value of the total anchoring force requirement before anchoring is 0; theta is an anchoring inclination angle; h 2 The height of a longitudinal connecting section of the dangerous soil body and the stable soil body is set; l, b and h are respectively the total height, the calculated width and the calculated depth of the dangerous soil body; tau is u Shear force is applied to a longitudinal connecting interface of a dangerous soil body and a stable soil body; w is a group of 1 Projecting the gravity center of the dangerous soil body to the horizontal distance of the empty face; w 2 Calculating the depth of the potential cracking section of the dangerous soil body; Ψ is the energy to break required for the unit area of the cross section to crack, and is determined by testing.
10. The method for designing the phyllostachys pubescens anchor rod seismic reinforcement containing the longitudinal crack rammed earth urban wall site according to claim 1, wherein in the step (8), the site safety factor F is calculated according to the following formula:
in the formula, T s Actual total anchoring force, T, available for the anchor rod u Is the requirement of the total anchoring force of the site.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT8912U1 (en) * | 2006-01-17 | 2007-02-15 | Millonig Stefan Dipl Ing | ANCHORAGE FOR PIE |
| CN103558088A (en) * | 2013-11-05 | 2014-02-05 | 兰州大学 | Earthen archaeological site anchoring laboratory test system |
| CN104088277A (en) * | 2014-07-16 | 2014-10-08 | 陕西师范大学 | Earthen ruin reinforcing anchor rod and design method thereof |
| CN104794365A (en) * | 2015-05-06 | 2015-07-22 | 南华大学 | Computation method for predicting ultimate bearing capacity of anchor rod based on mathematical model |
| CN106018102A (en) * | 2016-07-29 | 2016-10-12 | 兰州大学 | Rammed earth historic site group anchorage pullout test system |
-
2019
- 2019-07-16 CN CN201910641795.7A patent/CN110378013B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT8912U1 (en) * | 2006-01-17 | 2007-02-15 | Millonig Stefan Dipl Ing | ANCHORAGE FOR PIE |
| CN103558088A (en) * | 2013-11-05 | 2014-02-05 | 兰州大学 | Earthen archaeological site anchoring laboratory test system |
| CN104088277A (en) * | 2014-07-16 | 2014-10-08 | 陕西师范大学 | Earthen ruin reinforcing anchor rod and design method thereof |
| CN104794365A (en) * | 2015-05-06 | 2015-07-22 | 南华大学 | Computation method for predicting ultimate bearing capacity of anchor rod based on mathematical model |
| CN106018102A (en) * | 2016-07-29 | 2016-10-12 | 兰州大学 | Rammed earth historic site group anchorage pullout test system |
Non-Patent Citations (1)
| Title |
|---|
| 夯土介质中基于PS浆液的楠竹锚杆锚固特性;张景科等;《工程地质学报》;20161031;第24卷(第05期);第1028-1036页 * |
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