CN108978651B - Optimization determination method for rock slope prestress anchor rod reinforcement parameters - Google Patents
Optimization determination method for rock slope prestress anchor rod reinforcement parameters Download PDFInfo
- Publication number
- CN108978651B CN108978651B CN201810770680.3A CN201810770680A CN108978651B CN 108978651 B CN108978651 B CN 108978651B CN 201810770680 A CN201810770680 A CN 201810770680A CN 108978651 B CN108978651 B CN 108978651B
- Authority
- CN
- China
- Prior art keywords
- slope
- rock
- anchor
- anchor rod
- determining
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000011435 rock Substances 0.000 title claims abstract description 123
- 238000000034 method Methods 0.000 title claims abstract description 35
- 230000002787 reinforcement Effects 0.000 title claims abstract description 32
- 238000005457 optimization Methods 0.000 title claims abstract description 7
- 238000004873 anchoring Methods 0.000 claims abstract description 45
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 20
- 238000013461 design Methods 0.000 claims abstract description 18
- 238000012937 correction Methods 0.000 claims abstract description 15
- 238000010276 construction Methods 0.000 claims description 14
- 238000004364 calculation method Methods 0.000 claims description 12
- 238000012360 testing method Methods 0.000 claims description 11
- 230000000694 effects Effects 0.000 claims description 9
- 230000005484 gravity Effects 0.000 claims description 8
- 239000011378 shotcrete Substances 0.000 claims description 8
- 238000011835 investigation Methods 0.000 claims description 7
- 229910000831 Steel Inorganic materials 0.000 claims description 6
- 239000010959 steel Substances 0.000 claims description 6
- 230000009467 reduction Effects 0.000 claims description 5
- 238000011161 development Methods 0.000 claims description 3
- 238000010586 diagram Methods 0.000 claims description 3
- 238000011065 in-situ storage Methods 0.000 claims description 3
- 229920006395 saturated elastomer Polymers 0.000 claims description 3
- 238000013507 mapping Methods 0.000 claims description 2
- OIGNJSKKLXVSLS-VWUMJDOOSA-N prednisolone Chemical compound O=C1C=C[C@]2(C)[C@H]3[C@@H](O)C[C@](C)([C@@](CC4)(O)C(=O)CO)[C@@H]4[C@@H]3CCC2=C1 OIGNJSKKLXVSLS-VWUMJDOOSA-N 0.000 claims description 2
- 238000009864 tensile test Methods 0.000 claims 1
- 230000008901 benefit Effects 0.000 abstract description 4
- 238000011156 evaluation Methods 0.000 abstract description 3
- 230000002265 prevention Effects 0.000 abstract description 3
- 208000010392 Bone Fractures Diseases 0.000 description 7
- 206010017076 Fracture Diseases 0.000 description 7
- 238000004458 analytical method Methods 0.000 description 4
- 239000002689 soil Substances 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000008093 supporting effect Effects 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 238000009795 derivation Methods 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- NAWXUBYGYWOOIX-SFHVURJKSA-N (2s)-2-[[4-[2-(2,4-diaminoquinazolin-6-yl)ethyl]benzoyl]amino]-4-methylidenepentanedioic acid Chemical compound C1=CC2=NC(N)=NC(N)=C2C=C1CCC1=CC=C(C(=O)N[C@@H](CC(=C)C(O)=O)C(O)=O)C=C1 NAWXUBYGYWOOIX-SFHVURJKSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007405 data analysis Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/74—Means for anchoring structural elements or bulkheads
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/20—Securing of slopes or inclines
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A10/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE at coastal zones; at river basins
- Y02A10/23—Dune restoration or creation; Cliff stabilisation
Landscapes
- Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Mining & Mineral Resources (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Theoretical Computer Science (AREA)
- Computer Hardware Design (AREA)
- Evolutionary Computation (AREA)
- Geometry (AREA)
- General Physics & Mathematics (AREA)
- Piles And Underground Anchors (AREA)
- Pit Excavations, Shoring, Fill Or Stabilisation Of Slopes (AREA)
- Devices Affording Protection Of Roads Or Walls For Sound Insulation (AREA)
Abstract
The invention relates to the field of slope stability evaluation and landslide reinforcement and prevention and control, and relates to an optimization determination method for rock slope pre-stressed anchor rod reinforcement parameters, which comprises the following steps: determining basic physical and mechanical parameters of a slope to be reinforced; determining the stability coefficient of the rock slope; determining a rock slope stability correction coefficient; fourthly, determining anchor rod layout and anchor rod reinforcing anti-sliding force values; fifthly, determining the optimal incident angle of the rock mass side slope prestressed anchor rod; determining a quantitative relation between the bonding strength of the rock anchor and the uniaxial compressive strength of the rock anchor; step seven, determining the optimal anchoring length of the prestressed anchor rod; and step eight, determining the optimal design total length of the prestressed anchor rod. The method has good economic benefit and practical value in the slope reinforcement project, can accurately measure the incidence angle and the anchoring length of the anchor rod, and is more economic, reasonable and safe when the method is used for designing the prestressed anchor rod.
Description
Technical Field
The invention relates to the field of slope stability evaluation and landslide reinforcement and prevention, relates to an optimization determination method for rock slope pre-stressed anchor rod reinforcement parameters, and particularly relates to an optimization determination method for plane failure mode rock slope pre-stressed anchor rod reinforcement parameters.
Background
In recent years, the prestressed anchor rod has the characteristics of higher tensile strength, better reinforcing effect and low manufacturing cost, and is widely applied to the fields of slope reinforcement and landslide prevention and control. The prestressed anchor support belongs to active support, namely, the reinforcing and treating effect can be played without the displacement of a slope body. Because the support method applies prestress to the slope body of the side slope, the unstable slope body is compressed by the resilience of the steel bar after the anchoring, and the slope body is in a compressed state, the displacement of the slope body can be effectively reduced, and the reinforcement effect is better than that of the traditional treatment method. In addition, the prestressed anchor rod has the advantages of flexible arrangement, large reinforcing depth, capability of fully playing the strength and self-stability of rock-soil bodies, no damage to the integrity of the slope bodies in construction, high construction speed and the like. In the design of the prestressed anchor rod, the determination of the incident angle and the anchoring length of the prestressed anchor rod plays a crucial role in whether the supporting and reinforcing effect can be normally exerted, effectively reducing the manufacturing cost of the reinforcing engineering, shortening the construction period and the like, and is also a core technical problem of the prestressed anchor rod reinforcing engineering design. If the optimal incident angle and anchoring length can be obtained, the anchoring effect can be fully exerted, and the manufacturing cost and the construction period can be greatly saved.
Comprehensive analysis of a large number of engineering practices and technical economy shows that the incident angle and the anchoring length of the prestressed anchor rod are not only mechanical technical problems, but also economic benefits. The prestressed anchor rod is designed to achieve the purposes of minimizing the total length (including a free section, an anchoring section, a tensioning section and the like) of the prestressed anchor rod and minimizing the drilling workload on the premise of meeting the total anchoring force. At present, the determination of the incidence angle of prestress and the anchoring length of a bolt is estimated according to technical specifications of rock-soil anchoring and shotcrete supporting engineering (GB 50086-2015). The formula only considers the influence of the anchor rod and the parameters of the reinforcing body, and does not consider the influence of the potential slip surface inclination angle on the prestress value. In engineering practice, the incidence angle and anchoring length of the prestressed anchor often differ greatly from the regulations and recommendations of relevant specifications. For multiple rows of anchor rods, equal-length anchor rod construction is often adopted for construction convenience. However, for a slope with a plane sliding surface, the thickness of the sliding body at different elevations is different and is a variable rather than a constant, and therefore, the design method for the length of the equal anchor rod anchoring section is undoubtedly not an optimal reinforcement design scheme, because the required anchoring forces for the top, middle and toe parts of the slope are different, if the anchor rod anchoring length is designed uniformly according to the position where the required anchoring force is the largest, the waste is undoubtedly caused for the part with smaller required anchoring force, and meanwhile, the great waste is caused on the whole design length. Although the existing slope engineering also shortens the anchor rods at the top and the bottom of the slope qualitatively, the theory and design basis is lacked. The length of the anchor portion of the anchor is not constant, and therefore, the anchor reinforcing scheme is not optimal. The number and the length of anchor rods are increased too much to ensure the stability of the side slope, so that the reinforcement engineering cost, the construction period and the waste of manpower and material resources are caused.
Disclosure of Invention
Aiming at the defects, the invention provides an optimization determination method suitable for the reinforcement parameters of the prestressed anchor rod of the planar failure mode rock slope.
The technical scheme for solving the technical problems is as follows:
the method comprises the following steps: determination of basic physical and mechanical parameters of slope to be reinforced
Performing geotechnical engineering investigation and on-site in-situ test on the rocky slope according to the current geotechnical engineering investigation Specification (GB50021-2001) to obtain the standard value of the rock friction angle of the slope body of the slopeThe weight gamma of the rock mass, the cohesive force c, the slope angle beta of the rock slope and the slope height H; drawing a profile of the slope by a surveying and mapping method. And simultaneously, taking a plurality of points on the slope body of the side slope, respectively measuring the uniaxial compressive strength value Rc and the rock anchor limit bonding strength value qr of the rock through a rock saturated uniaxial compressive strength test and an anchor rod limit pulling test, and drawing a qr and Rc relation curve.
Step two: determination of rock slope stability coefficient Fs
Equivalent internal friction angle psi of rock massdThe standard value of the internal friction angle of the rock block can be determined by the step oneDetermining according to the rock mass fracture development degree multiplied by the reduction coefficient listed in the table 1; according to the technical specification of building slope engineering (GB50330-2002), the inclination angle of the plane damage potential sliding surface of the rock slope can be determined to be
TABLE 1 reduction coefficient of internal friction angle of slope rock mass
Determining the stability coefficient Fs of the plane sliding method by using a formula (1) as follows:
in the formula: Ψ d is an equivalent internal friction angle of the rock mass, and theta is an inclination angle of a plane damage potential slip plane of the slope of the rock mass.
Step three: rock slope stability correction coefficient delta FSIs determined
Defining a slope stability correction factor Δ FSThe difference between the slope safety coefficient K and the slope overall stability coefficient Fs is as follows:
ΔFS=K-FS (2)
in the formula: Δ FSSlope stability correction factor
K-the slope safety factor, the value is as shown in Table 5.3.1 in the technical Specification for supporting foundation pits of buildings (JGJ120-2012), and is specifically shown in Table 2 below:
TABLE 2 Stable safety factor of slope
Step four: anchor rod layout and determination of anchor rod reinforcing anti-slip force value
1) Determination of side slope anchor rod laying interval
And determining the anchor rod layout condition according to the regulation of 10.3 in the current technical Specification for building slope engineering (GB 50030-2013). The anchor rods are arranged in a row and column manner; the horizontal distance between the anchor rods is not less than 1.5 m; the vertical spacing of the anchor rods is not less than 2.0 m. The width of the landslide body is set to be LbThe transverse distance between the prestressed anchor rods is b, wherein b is the edge of the first anchor rod at the two ends of the slip mass and is far away from the edge of the slip mass, and the number of the anchor rods in each row is as follows:
according to the technical Specification of construction slope engineering (GB50030-2013), the distance between the first row of anchor rods and the top of the slope is 1.5 m-2.0 m. If the vertical interval of stock is hm, the side slope height is H, and first row stock is apart from the top of the slope distance and is H1, then the stock row number is:
2) determination of the stability correction factor Δ Fsri assumed by a single anchor
Vertical strip division is carried out to the rock mass side slope body, and the effective effect scope of single stock is assumed and is got the sum of equalling divide of scope between this stock and the adjacent stock, so the gliding force that the stock bore the rock mass and produce is that the rock mass gravity of potential slip surface top in the effective effect scope produces, and then the proportion of the stability correction coefficient that each single stock bore can be divided according to the proportion of the rock mass gravity who undertakes:
gri-rock mass gravity borne by i anchor rods in the r-th row
3) Determining the required reinforcing anti-sliding force value of each anchor rod of the rock mass side slope:
ΔFri=ΔFsri×Grisinθ (6)
in the formula: Δ Fri — the amount of reinforcement slip resistance applied by the i bolts in the r-th row.
Step five: determination of optimal incident angle of rock mass side slope prestressed anchor rod
Aiming at the plane failure type landslide, the inclination angles of the rock mass side slope fracture surfaces are the same, so the incidence angle alpha of the anchor rod driven into the rock mass is the same, and the reinforcement prestress value delta fri is determined according to the formula (8):
ΔFri=Δfri sin(α+θ)tanΨd+Δfri cos(α+θ) (7)
derivation of α in the formula (8) formula (9)
In the formula: Ψ d-is an equivalent internal friction angle of the rock body;
theta-is the inclination angle of the rock slope fracture surface;
alpha-anchor angle.
Let equation (9) equal zero, and perform extremum analysis on equations (7) and (8) to obtain: Δ fri takes a maximum value when α ═ Ψ d- θ. According to the specification of item 4.6.5 in technical Specification of geotechnical anchoring and shotcrete support engineering (GB50086-2015), the reinforcement incident angle of the slope anchor rod is preferably kept from forming an angle of-10 degrees to +10 degrees with the horizontal plane, so that the optimal incident angle for the reinforcement of the slope anchor rod is determined as follows:
(1) when the Ψ d-theta is larger than or equal to 10 degrees, the optimal incidence angle for reinforcing the slope anchor rod is alpha' ═ Ψ d-theta;
(2) when Ψ d- θ is less than 10 °, the slope anchor reinforcement optimum incidence angle is α' 10 °.
Step six: determination of quantitative relation between rock anchor bonding strength and uniaxial compressive strength thereof
According to data analysis obtained by a large number of field tests, the relation curve of the rock anchor ultimate bonding strength and the rock uniaxial compressive strength conforms to an ln function curve, so that the function relation of the rock anchor bonding strength qr and the rock uniaxial compressive strength Rc can be assumed as follows:
qr=alnRc+b(10)
in the formula, the values of a and b can be obtained by fitting the rock anchor ultimate bonding strength and rock uniaxial compressive strength of a plurality of different measuring points measured by the test method in the step one by using a least square method, and the calculation process is as follows: equation (10) is taken as a linear combination of two elementary functions (11) (12):
and (3) setting m as the number of test data, and knowing the calculation principle by a least square method:
substituting the calculation result of the formula into the formula (18) to calculate a and b:
step seven: determination of optimal anchoring length of prestressed anchor
Substituting the rock uniaxial compressive strength Rc determined by the rock saturated uniaxial compressive strength test in the first step into the formula (10) in the sixth step to obtain the rock anchor ultimate bonding strength qr, and determining the optimized anchoring body length delta lri of each anchor rod according to a calculation formula of the anchoring force of 4.6.10 in technical specification of rock-soil anchoring and shotcrete support engineering (GB 50086-2015):
in the formula: Δ lri-row r i anchors optimize anchor length (m);
d, the diameter (mm) of the anchor rod anchoring body;
qr-ultimate bond strength (MPa) between the surface of the anchor and the surrounding rock mass;
delta fri-reinforcement prestress value (kN) of i anchor rods in the r-th row;
k' -the bond resistance to plucking safety coefficient between the anchor and the surrounding rock mass, the values are taken according to Table 3;
n is the number of the steel bars or steel strands;
xi-coefficient of reducing the bonding strength of the interface, and is 0.70-0.85;
psi, coefficient of influence of anchoring length on bond strength, was taken as in table 4.
TABLE 3 bond resistance to plucking safety factor between anchor and surrounding rock mass
TABLE 4 influence coefficient psi of anchoring length on bond strength
Step eight: determination of optimal designed total length of prestressed anchor
1) Determining the distance from the slope of the rock mass slope at each anchor rod construction position to the intersection point of the anchor rod and the potential slip surface according to a formula (20) as the free section length delta Lri of the anchor rod, and deducing the principle:
2) the optimum overall design length of the bolt is determined according to equation (21):
lri=ΔLri+Δlri (21)
in the formula: lri-total length of the design of the i anchor rods in the r-th row;
delta Li-length of free section of i anchor rods in the r-th row;
α' -optimum angle of incidence of the anchor;
beta-the slope angle of the rock mass side slope;
theta is the inclination angle of the plane damage potential slip plane of the rock slope;
hri is the slope height at the intersection of the ith row of i anchor rods and the slope surface of the rock body.
The principle is as follows: the principle of the invention for calculating the length of the anchoring free section of the prestressed anchor is as follows:
the slope height hi at the intersection of the ith anchor rod and the rock slope surface, the free section length delta Li of the ith anchor rod, the optimal incident angle alpha 'of the anchor rod, the dip angle theta of the rock slope surface damage potential slip surface and the included angle alpha' + theta of the anchor rod and the potential slip surface.
Anchoring free length delta Li of ith anchor rod:
compared with the prior art, the invention has the beneficial effects that: aiming at the defects of high reinforcement engineering cost, long construction period and the like caused by the traditional anchor rod reinforcement design method, on the basis of the analysis of the prestress anchor rod side slope reinforcement mechanism and the evaluation of the reinforcement stability, the optimal incident angle and the anchoring section length of the rock slope anchor rod with a plane potential slip surface are optimally designed, the optimal incident angle and the anchoring section length under the premise of ensuring the maximum potential of the prestress anchor rod can be found and determined, and the design and measurement method of the optimal incident angle and the anchoring section length of the prestress anchor rod is provided, so that the aims of saving the engineering cost and the construction period under the premise of ensuring the safety and the stability of the rock slope are fulfilled. By comparing the design length of the anchor rod determined by the correction software, the design method greatly reduces and optimizes the design length of the anchor rod, and has good economic benefit and practical value in slope reinforcement engineering. The method not only can accurately measure the incident angle and the anchoring length of the anchor rod, but also is more economical, reasonable and safe to design the prestressed anchor rod by applying the method.
Drawings
FIG. 1 is a flow chart of the present invention;
FIG. 2 is a diagram illustrating the relationship between qr and Rc functions;
FIG. 3 illustrates the Gri calculation range according to the present invention;
fig. 4 is a schematic diagram of calculation of the distance from the slope surface to the potential slip surface of the anchor rod.
Detailed Description
The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.
To better illustrate the present invention, the feasibility of the method is now described in detail in conjunction with a specific engineering application to demonstrate the practical significance and value of the method.
The specific implementation and calculation process is as follows:
the method comprises the following steps: determination of basic physical and mechanical parameters of slope to be reinforced
According to the current geotechnical engineering investigation Specification (GB50021-2001) on a rock slope, through geotechnical engineering investigation and on-site in-situ test, the landslide is 35m high and 12m wide, the slope angle beta of the slope is 70 degrees, the cohesive force c is 5KPa, and the internal friction angleIs 40 degrees and the severe gamma is 20kN/m3. The qr and Rc test values are shown in FIG. 2. Has no underground water function.
Step two: determination of rock slope stability coefficient Fs
Determining that the reduction coefficient of the internal friction angle of the slope rock mass is 0.87 according to the development degree of the rock mass fracture obtained by the investigation in the step one and referring to table 1, so that the reduction coefficient can be defined by the equivalent internal friction angle Ψ d of the rock mass: Ψ d — 40 ° × 0.87 — 34.8 °; according to the technical specification of building slope engineering (GB50330-2002), the inclination angle of the plane damage potential sliding surface of the rock slope can be determined to be
Determining the stability coefficient Fs of the plane sliding method by using a formula (1) as follows:
step three: rock slope stability correction coefficient delta FSIs determined
According to the existing technical code of building slope engineering (GB50030-2013), the safety grade of the slope is set as two levels, and the safety factor K of the slope can be determined to be 1.3.
Defining a slope stability correction factor Δ FSThe difference between the slope safety coefficient K and the slope overall stability coefficient Fs is as follows:
ΔFS=K-FS=1.3-0.49=0.81
step four: anchor rod layout and determination of anchor rod reinforcing anti-slip force value
1) Determination of side slope anchor rod laying interval
The anchor rod row spacing is fixed as 5m, and the first row anchor rod is 5m away from the top of the slope. The number of rows of anchor rods is represented by formula
The transverse spacing of the anchor rods is set to be 3 m. The number of anchor rods in each row is represented by the formula
2) Determination of stability correction coefficient delta F borne by single anchor rod and reinforcement anti-sliding force value required by each anchor rod of rock mass slope
Vertical strip division is carried out to the rock mass side slope body, and the effective effect scope of single stock is assumed and is taken the sum of dividing equally of scope between this stock and the adjacent stock, so the gliding force that the stock undertakes the rock mass and produce is that the rock mass gravity of potential slip surface top produces in the effective effect scope, then the proportion of the stability correction coefficient that each single stock undertakes can be divided according to the proportion of the rock mass gravity that undertakes, and the calculation is as follows:
step five: determination of optimal incident angle of rock mass side slope prestressed anchor rod
The slope fracture surface of the rock body slope has the same inclination angle due to the fact that the slope fracture surface is only directed at the plane failure type landslide, the incidence angle alpha of the anchor rod driven into the rock body is the same, and the reinforcement prestress value delta fri is determined according to the formula (8):
ΔFri=Δfrisin(α+θ)tanΨd+Δfricos(α+θ) (7)
derivation of α in the formula (8) formula (9)
In the formula: Ψ d-is an equivalent internal friction angle of the rock body;
theta-is the inclination angle of the rock slope fracture surface;
alpha-anchor angle.
Let equation (9) equal zero, and perform extremum analysis on equations (7) and (8) to obtain: when α ═ ΨdΔ fri takes a maximum value at-30.2 °. According to the specification of item 4.6.5 in technical specification of geotechnical anchoring and shotcrete support engineering (GB50086-2015), the reinforcement incident angle of the slope anchor rod is preferably kept from forming an angle of-10 degrees to +10 degrees with the horizontal plane, so that the optimum incident angle for reinforcing the slope anchor rod is alpha' 10 degrees.
Substituting α' into equation (8) for 10 ° results in the following:
step six: determination of quantitative relation between rock anchor bonding strength and uniaxial compressive strength thereof
The test data totaled 19 groups, i.e. m is 19. Calculated by equations (13) to (17):
substituting the data into equation (18) yields:
a=0.73,b=-1.64。
therefore, the function relation of the rock anchor bonding strength qr and the rock uniaxial compressive strength Rc is as follows:
qr=0.73lnRc-1.64
step seven: determination of optimal anchoring length of prestressed anchor
The parameters required by calculation are determined according to 4.6 in the current technical Specification for rock-soil anchoring and shotcrete support engineering (GB 50086-2011). The rod body is a twisted steel with the diameter of 16 mm. n is 1, K is 2.0; qr 1.3 Mpa; d is 50 mm; d is 16 mm; ψ is 1.0 and ξ is 0.82.
According to the technical specification of geotechnical anchoring and shotcrete support engineering (GB50086-2015) 4.6.10 item calculation formula (see formula 19), the calculation result is as follows:
1 | 2 | 3 | 4 | 5 | 6 | 7 | |
Δlri(m) | 2.20 | 2.32 | 2.54 | 2.36 | 2.20 | 1.80 | 1.37 |
step eight: determination of optimal designed total length of prestressed anchor
Determining the distance from the slope of the rock body slope at the construction position of each anchor rod to the intersection point of the anchor rod and the potential slip plane according to a formula (20) as the free section length delta Lri of the anchor rod, determining the optimal designed total length Lri of each anchor rod according to a formula (21), and calculating the following results:
the above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (4)
1. An optimization determination method for rock slope pre-stressed anchor rod reinforcement parameters is characterized by comprising the following steps:
determining basic physical and mechanical parameters of a slope to be reinforced: carrying out geotechnical engineering investigation and on-site in-situ test on the rocky slope according to the current geotechnical engineering investigation Specification (GB50021-2001) to obtain the standard value of the internal friction angle of the rock of the slope body of the side slopeThe weight gamma of the rock mass, the cohesive force c, the slope angle beta of the rock slope and the slope height H; drawing a side slope section diagram by using a surveying and mapping method, simultaneously taking a plurality of points on a side slope body, and respectively measuring a rock uniaxial compressive strength value Rc and a rock anchor ultimate bonding strength value q by a rock saturated uniaxial compressive strength test and an anchor rod ultimate tensile testrAnd drawing qrRc relation curve;
step two, determining the stability coefficient F of the rock slopes: equivalent internal friction angle psi of rock massdFrom the standard value of the internal friction angle of the rockDetermining according to the rock mass crack development degree multiplied by the reduction coefficient of the internal friction angle of the slope rock mass; determining the inclination angle of the plane damage potential sliding surface of the rock mass side slope according to the technical specification of building side slope engineering (GB50330-2002)Determination of rock slope stability coefficient F by plane sliding methodsComprises the following steps:
in the formula: ΨdThe equivalent internal friction angle of the rock mass is theta, and the inclination angle of the plane damage potential slip plane of the slope of the rock mass is theta;
step three, determining the rock slope stability correction coefficient delta Fs:
Slope stability correction coefficient Delta FsIs a slope safety coefficient K and a slope integral stability coefficient FsThe difference of (a) is:
△Fs=K-Fs
in the formula: delta FsThe coefficient is a slope stability correction coefficient, K is a slope safety coefficient, and the value of K is shown in table 5.3.1 in the technical specification of building foundation pit support (JGJ 120-2012);
step four, determining anchor rod layout and anchor rod reinforcing anti-slip force value delta Fri:
1) Determining the arrangement distance of the side slope anchor rods: determining the arrangement condition of anchor rods according to the regulation of 10.3 in the current technical Specification for building slope engineering (GB50030-2013), wherein the anchor rods are arranged in a determinant manner; the horizontal distance between the anchor rods is not less than 1.5 m; the vertical spacing of the anchor rods is not less than 2.0m, and the width of the landslide body is LbThe transverse distance between the prestressed anchor rods is b, wherein b is the distance between the first anchor rod at the two ends of the slip mass and the edge of the slip mass, and the number n of the anchor rods in each rowHComprises the following steps:
according to the technical Specification of construction slope engineering (GB50030-2013), the distance between the first row of anchor rods and the top of the slope is 1.5-2.0 m, and the vertical distance between the anchor rods is hmThe height of the side slope is H, and the distance from the first row of anchor rods to the top of the slope is H1The number of rows of anchor rods nvComprises the following steps:
2) stability correction factor delta F borne by single anchor rodsriDetermination of (1):
vertical strip division is carried out to the rock mass side slope body, and the effective effect scope of single stock is assumed and is got the sum of equalling divide of scope between this stock and the adjacent stock, so the gliding force that the stock bore the rock mass and produce is that the rock mass gravity of potential slip surface top in the effective effect scope produces, and then the proportion of the stability correction coefficient that each single stock bore can be divided according to the proportion of the rock mass gravity who undertakes:
in the formula: griThe rock mass gravity borne by the i anchor rods in the r-th row is less than or equal to nv,i≤nH;
3) Determining the required reinforcing anti-sliding force value of each anchor rod of the rock mass side slope:
△Fri=△Fsri×Grisinθ
in the formula: delta FriA reinforcing anti-slip value applied to the ith row of i anchor rods;
step five, determining the optimal incident angle alpha' of the rock slope prestressed anchor rod:
for plane failure type landslides, the slope fracture surfaces of the rock body side slopes have the same inclination angle, so that the incidence angle alpha of the anchor rod driven into the rock body is the same, and the reinforcing prestress value delta fri:
Deriving α in the above formula:
in the formula: ΨdThe equivalent internal friction angle of the rock mass; theta is the inclination angle of the rock slope fracture surface; alpha is the anchor rod incidence angle;
according to the specification of item 4.6.5 in technical Specification of geotechnical anchoring and shotcrete support engineering (GB50086-2015), the reinforcement incident angle of the slope anchor rod is preferably kept from forming an angle of-10 degrees to +10 degrees with the horizontal plane, so that the optimal incident angle for the reinforcement of the slope anchor rod is determined as follows:
(1) when t isdWhen the angle is larger than or equal to 10 degrees, the optimal incidence angle for reinforcing the slope anchor rod is alpha' ═ psid-θ;
(2) When t isdWhen theta is less than 10 degrees, the optimal incidence angle for reinforcing the slope anchor rod is alpha' which is 10 degrees;
step six, determining the ultimate bonding strength q of the rock anchorrQuantitative relation with uniaxial compressive strength Rc thereof;
step seven, determining the optimal anchoring length delta l of the prestressed anchor rodri;
Step eight, determining the optimal design total length of the prestressed anchor rodDegree lri。
2. The method for optimally measuring the reinforcement parameters of the prestressed anchor rod of the rock slope as claimed in claim 1, wherein the method for determining the quantitative relationship between the ultimate bonding strength of the rock anchor and the uniaxial compressive strength of the rock anchor is as follows: the relation curve of the ultimate bonding strength of the rock anchor and the uniaxial compressive strength of the rock conforms to an ln function curve, so that the ultimate bonding strength q of the rock anchor is assumedrThe function relation with the rock uniaxial compressive strength Rc is as follows:
qr=aln Rc+b
the values of a and b in the formula are obtained by least square fitting.
3. The method for optimally measuring the reinforcement parameters of the prestressed anchor of the rock slope as claimed in claim 2, wherein the optimal anchoring length Δ l of the prestressed anchor is determinedriThe method comprises the following steps:
according to the technical specification of geotechnical anchoring and shotcrete support engineering (GB50086-2015) 4.6.10 item anchoring force calculation formula, the length delta l of each anchor rod optimized anchoring body can be determinedri:
In the formula: delta lriOptimizing the length (m) of an anchoring body for the i anchor rods in the r row; d is the diameter (mm) of the anchor rod anchoring body; q. q.srUltimate bond strength (MPa) between the surface of the anchor and the surrounding rock mass; delta friReinforcing the prestress value (kN) of the i anchor rods in the r-th row; k' is the bonding anti-pulling safety coefficient between the anchoring body and the surrounding rock mass, and the value is taken according to the table 3; n is the number of the steel bars or the steel strands; xi is the coefficient for reducing the bonding strength of the interface, and is 0.70-0.85; psi is the coefficient of influence of the anchoring length on the bonding strength.
4. The method for optimally measuring the reinforcement parameters of the prestressed anchor of the rock slope as claimed in claim 3, wherein the method for determining the optimal design total length of the prestressed anchor is as follows:
1) determining the distance from the slope of the rock body slope at each anchor rod construction position to the intersection point of the anchor rod and the potential slip surface as the length delta L of the free section of the anchor rodri:
2) Determination of the optimum overall design length l of the anchorri:
lri=△Lri+△lri
In the formula: lriDesigning the total length of i anchor rods in the r-th row; delta Lri-the length of the free section of the i anchor rods in the r row; alpha' is the optimal incidence angle of the anchor rod; beta is the slope angle of the rock mass side slope; theta is the inclination angle of the plane damage potential slip plane of the rock slope; h isriThe slope height of the intersection point of the ith row of i anchor rods and the slope surface of the rock body.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201810770680.3A CN108978651B (en) | 2018-07-13 | 2018-07-13 | Optimization determination method for rock slope prestress anchor rod reinforcement parameters |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201810770680.3A CN108978651B (en) | 2018-07-13 | 2018-07-13 | Optimization determination method for rock slope prestress anchor rod reinforcement parameters |
Publications (2)
Publication Number | Publication Date |
---|---|
CN108978651A CN108978651A (en) | 2018-12-11 |
CN108978651B true CN108978651B (en) | 2021-05-18 |
Family
ID=64537481
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN201810770680.3A Active CN108978651B (en) | 2018-07-13 | 2018-07-13 | Optimization determination method for rock slope prestress anchor rod reinforcement parameters |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN108978651B (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN110263424A (en) * | 2019-06-18 | 2019-09-20 | 贵州正业工程技术投资有限公司 | Group's pulling force effect ball crown type Slope Stability Evaluation method based on simple flat surface sliding scale |
CN110512625B (en) * | 2019-08-23 | 2021-04-06 | 郑州安源工程技术有限公司 | Grouting and anchor rod double-reinforcing method for vertical crack of slope rock mass |
CN110688747B (en) * | 2019-09-19 | 2022-05-06 | 昆明理工大学 | Rock slope anchoring calculation method based on safety and economy multi-objective optimization |
CN111310356B (en) * | 2020-03-04 | 2023-08-11 | 山西水务集团建设投资有限公司 | Stability evaluation method of inverted arch retaining wall suitable for loess slope reinforcement |
CN111832109B (en) * | 2020-07-14 | 2022-08-05 | 重庆大学 | Design method of rock slope gravity type retaining wall without camber structural surface |
CN113326547B (en) * | 2021-03-19 | 2022-11-01 | 青岛理工大学 | Slope anchor rod anchoring method based on stress compensation |
CN114254514B (en) * | 2021-12-23 | 2023-05-23 | 中国水利水电科学研究院 | Stable analysis method for soil and rock slope cracking-dumping collapse damage mode |
CN117845964A (en) * | 2024-01-12 | 2024-04-09 | 北旺路桥建设有限公司 | Road construction slope supporting device and construction method based on geological detection |
CN117807690B (en) * | 2024-03-01 | 2024-07-05 | 济南轨道交通集团有限公司 | Method and system for selecting bonding strength of anchoring body of rock-soil slope or foundation pit |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2248951A1 (en) * | 2009-05-08 | 2010-11-10 | Keller Holding gmbh | Method and device for determining the axial force progression in a pressure-grouted anchor |
CN104988918A (en) * | 2015-07-24 | 2015-10-21 | 青岛理工大学 | Method for measuring optimal anchoring length of deep foundation pit prestressed anchor rod |
CN106485031A (en) * | 2016-11-04 | 2017-03-08 | 青岛理工大学 | Optimal design method for reinforcing length of prestressed anchor rod of weathered rock slope |
CN106844927A (en) * | 2017-01-13 | 2017-06-13 | 青岛理工大学 | Method for measuring anchoring optimization parameters of rock slope with double slip planes |
-
2018
- 2018-07-13 CN CN201810770680.3A patent/CN108978651B/en active Active
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2248951A1 (en) * | 2009-05-08 | 2010-11-10 | Keller Holding gmbh | Method and device for determining the axial force progression in a pressure-grouted anchor |
CN104988918A (en) * | 2015-07-24 | 2015-10-21 | 青岛理工大学 | Method for measuring optimal anchoring length of deep foundation pit prestressed anchor rod |
CN106485031A (en) * | 2016-11-04 | 2017-03-08 | 青岛理工大学 | Optimal design method for reinforcing length of prestressed anchor rod of weathered rock slope |
CN106844927A (en) * | 2017-01-13 | 2017-06-13 | 青岛理工大学 | Method for measuring anchoring optimization parameters of rock slope with double slip planes |
Non-Patent Citations (1)
Title |
---|
预应力锚杆复合土钉支护边坡的优化设计研究;潘信梅等;《工程建设》;20161231(第06期);全文 * |
Also Published As
Publication number | Publication date |
---|---|
CN108978651A (en) | 2018-12-11 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN108978651B (en) | Optimization determination method for rock slope prestress anchor rod reinforcement parameters | |
Wang et al. | Study on failure mechanism of roadway with soft rock in deep coal mine and confined concrete support system | |
CN106485031B (en) | Optimal design method for reinforcing length of prestressed anchor rod of weathered rock slope | |
CN109235509B (en) | Optimization determination method for reinforcement parameters of rock slope anchor rod with forward double sliding surfaces | |
CN109506614B (en) | Method for judging large deformation of layered surrounding rock | |
CN109271744B (en) | Dump base bearing capacity calculation method based on limit upper limit method | |
CN114154211A (en) | Design method of high ground stress soft rock tunnel supporting structure, computer device and product | |
CN108222969A (en) | A kind of Design of Tunnel method based on method of safety coefficients | |
CN114297767A (en) | Deep-concave mine excavation slope active anchoring optimization design method | |
Türkmen et al. | Out-of-plane behavior of clay brick masonry walls retrofitted with flexible deep mounted CFRP strips | |
CN108536978A (en) | A method of prevent High Concrete Dam gallery crown from cracking | |
Wu et al. | Seismic behavior of high strength concrete composite walls with embedded steel truss | |
CN110378013B (en) | Anti-seismic reinforcement design method for phyllostachys pubescens anchor rods in urban wall site containing longitudinal crack rammed earth | |
CN108119147B (en) | A kind of Soft Rock Tunnel Excavation and preliminary bracing method | |
Zhou et al. | Mechanical properties and seismic behavior of confined masonry walls in freeze-thaw environment | |
Topuzi et al. | A new technique for the seismic retrofit of Slab-Column connections | |
CN104153341B (en) | A kind of flatly moving type soil pressure surveys model test device | |
CN114439058B (en) | Classification early warning identification and jacking treatment process for dislocation deformation of deformation joint of pipe gallery | |
CN108104823B (en) | A kind of buried soft rock tunnel construction method | |
CN113158294B (en) | Design method of slowly-inclined fold line sliding surface side slope deep-buried shear pile supporting structure | |
CN101793037B (en) | Surface sedimentation rate method of rockfill roadbed high-fill structure | |
CN108595807A (en) | A kind of computational methods of roadway floor release well width | |
CN213296313U (en) | Flat plate load loading device for carbonatite boulder dynamic compaction foundation | |
CN216714427U (en) | Asymmetric primary support structure for large-span dome of bedding surface development surrounding rock | |
Kožul et al. | Nelinearna statička analiza ponašanja postojeće zidane zgrade na potresno djelovanje |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PB01 | Publication | ||
PB01 | Publication | ||
SE01 | Entry into force of request for substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
GR01 | Patent grant | ||
GR01 | Patent grant |