CN103488829B - A kind of slope anchorage layout method - Google Patents

Abstract

The invention discloses a kind of slope anchorage layout method, comprise the following steps: in a side slope, gather many groups cylindrical sample of rock mass in side slope, obtain the Mechanics Parameters of Rock Mass value of this side slope by triaxial test; Slope body is decomposed into by particle and is formed, according to the above-mentioned Mechanics Parameters of Rock Mass calculating, utilize Lagrangian finite difference method to carry out the stress field calculation of side slope, obtain the stress field value of each particle; That calculates each particle causes the destroyed minimum principal stress minimum of this particle place side slope, destroys minimum; The destruction minimum that utilization calculates, calculates the shear strength of rock of each particle in side slope and the ratio of the inner shear stress of slope body, i.e. the safety coefficient of each particle; The particle that all safety coefficients are less than to the safety coefficient design load that national regulation specifies is as the cloth office point that need to carry out slope anchorage. The invention provides a kind of method that can determine the key area that Slope body needs reinforcement.

Description

A kind of slope anchorage layout method

Technical field

The invention belongs to slope project technical field, particularly a kind of slope anchorage layout method.

Background technology

Rock slope is the major project carrier in the engineering construction of mountain area, especially in In Southwest China,High slope problem has almost become primary engineering geology and the rock mass mechanics problem of key project construction, is controllingThe feasibility of engineering construction and on-road efficiency. The stability state of engineering slope, is related to the one-tenth of engineering constructionLose and safety, to the construction feasibility of whole engineering, security plays an important role, and at great Cheng veryOn degree, affect construction investment and utilization benefit.

Traditional complicated high gradient slope reinforcement means is to have a destruction face, meter in hypothesis Slope bodyThereby the safety coefficient of calculating on destruction face instructs Design of Reinforcement [with reference to every profession and trade specification]. This method veryEffectively, but very conservative, greatest drawback is to identify the key area of slope reinforcement, thereby haves no alternative but itUnder whole hypothesis destruction face is reinforced comprehensively, cause the significant wastage of manpower and financial resources.

The key area of slope failure refers in Slope body that each particle safety coefficient is lower than the district of design loadTerritory. Key area does not destroy, and other region just can not be destroyed, and key area is the emphasis of reinforcing.

Summary of the invention

The present invention, in order to overcome the shortcoming of traditional high gradient slope reinforcement means, has proposed one and can determine limitThe key area that slope, slope body needs reinforcement needs the method for the cloth office point of carrying out slope anchorage, passes through the partyMethod can reduce blindly reinforces, and reduces construction investment, and the method is fully theoretical, and accuracy is good, energyUnder enough conditions being protected completely in Slope body reinforcing security performance, determine that Slope body needs reinforcementCloth office point.

Technical scheme provided by the invention is:

A kind of slope anchorage layout method, comprises the following steps:

Step 1, in a side slope, gather many groups cylindrical sample of rock mass in side slope, many in every groupIn 3 samples, then utilize triaxial test to calculate respectively the following Mechanics Parameters of Rock Mass of every group of sample: bulletProperty modulus, Poisson's ratio, compression strength, cohesive strength and internal friction angle, will organize the rock mass mechanics of sample moreMean parameter is as the Mechanics Parameters of Rock Mass value of this side slope; Wherein, three axles in described triaxial testRefer to three-dimensional x, y and z axle, have 3 samples at least in every group of sample, just can complete triaxial test.

Step 2, Slope body is decomposed into by particle and is formed, according to the above-mentioned elastic modelling quantity calculating,Poisson's ratio, compression strength, cohesive strength and internal friction angle parameter, utilize Lagrangian finite difference methodCarry out the stress field calculation of side slope, obtain the stress field value of each particle, and extract each matterThe maximum principal stress σ of point₁With minimum principal stress σ₃；

Step 3, calculate each particle cause the destroyed minimum principal stress of this particle place side slope minimumValue, destroys minimum σ_3c, computational methods are as follows: σ_3c＝(σ₁-R_c)/tgθ², wherein, σ₁?Large principal stress, R_cThe compression strength in the Mechanics Parameters of Rock Mass value of this side slope,φ isInternal friction angle in the Mechanics Parameters of Rock Mass value of this side slope; Wherein, the described particle place side slope that causes is brokenBad minimum principal stress minimum destroys minimum σ_3c, whether the side slope at a particle place is destroyed depends onIn maximum principal stress σ₁With minimum principal stress σ₃Between difference, difference is larger, more easily cause destroy,Therefore at maximum principal stress σ₁The constant situation of value under, minimum principal stress σ₃Less, difference is larger,More easily cause the side slope at this particle place destroyed, therefore destroy minimum σ_3cJust refer to and do not destroyingSituation under minimum principal stress σ₃The minimum of a value that can reach.

The σ that step 4, utilization calculate_3c, the shear strength of rock τ of each particle in calculating side slope_cRatio with the inner shear stress τ of slope bodyBe the safety coefficient K of each particle, computational methodsAs follows:

$K=\frac{{\mathrm{\σ}}_1-{\mathrm{\σ}}_{3c}}{{\mathrm{\σ}}_1-{\mathrm{\σ}}_3};$

Step 5, all safety coefficient K are less than to the particle of the safety coefficient design load that national regulation specifiesAs the cloth office point that need to carry out slope anchorage.

Preferably, described slope anchorage layout method, gathers rock mass in side slope in described step 1When cylindrical sample, can gather 3 groups of samples, the sample size in every group is 5.

Preferably, described slope anchorage layout method, according to the side slope calculating in step 1Each particle extracting in cohesive strength, internal friction angle parameter and step 2 in Mechanics Parameters of Rock MassMaximum principal stress, minimum principal stress data are drawn out the Mohr-Coulomb's strength theory figure of each particle, rootAccording to Mohr-Coulomb's strength theory figure, calculate the shear strength of rock τ of each particle in side slope_cIn the body of slopeThe shear stress τ of portion, computational methods are as follows: ${\mathrm{\τ}}_c=\frac{{\mathrm{\σ}}_1-{\mathrm{\σ}}_{3c}}{2}cos\mathrm{\φ},\mathrm{\τ}=\frac{{\mathrm{\σ}}_1-{\mathrm{\σ}}_3}{2}\sin 2\mathrm{\θ},$ θ isThe shear surface of each particle and the angle of biggest principal stress direction,Can calculate thus everyThe safety coefficient K of a particle.

Preferably, described slope anchorage layout method, also comprises step 6, according in step 5To slope, opposite side slope, the cloth office point body that need to carry out slope anchorage carry out anchoring, comprise the following steps: (1)According to the border of the cloth office point that need to carry out slope anchorage described above, calculate the dark of Slope body anchoringDegree; (2) to carrying out the cloth office point of slope anchorage needed unit are anchor force F while carrying out anchoringCalculating, computational methods are as follows: F=(K₀-K)(σ₁-σ₃)/K₀(K＜K₀), wherein, K₀For countryThe safety coefficient design load of regulation and stipulation.

Wherein, the triaxial test described in step 1 is the abbreviation of triaxial compression test, is that mensuration rock is strongA kind of comparatively perfect method of degree and deformation parameter, triaxial test completes by triaxial apparatus,Triaxial apparatus by balancing gate pit, axially loading system, apply ambient pressure system, interstitial hydraulic pressure measuresSystem composition. The key step of test method is as follows: rock is cut into cylinder and is enclosed within rubber membrane, putIn the balancing gate pit of sealing, then in balancing gate pit, be pressed into water, test specimen around being subject to, all directions is pressedPower, and hydraulic pressure is remained unchanged in whole process of the test, at this moment in test specimen respectively to three principal stresses allEquate, therefore shear stress do not occur. And then by transmission rod, test specimen is applied to vertical pressure, like this,Vertical principal stress is just greater than level to principal stress, and in the time that vertical principal stress increases gradually, test specimen is cut finallyAnd destroy, thereby test out intensity and the Mechanics Parameters of Rock Mass of rock.

The stress field calculation that utilization Lagrange finite difference method described in step 2 carries out side slope is existingHave technology, FLAC3D be utilize Lagrangian finite difference method carry out side slope stress field calculation pointAnalyse program, FLAC3D is to be that Geological Engineering application is opened by American I tascaConsultingGroup companyThe continuous media Explicit finite difference computational methods of sending out are current general three-dimensionals of Geotechnical Engineering circle in the worldFast Lagrangian analysis program. These computational methods are mainly applicable to the mechanics of analog computation material of rock and soilBehavior and rock-soil material reach the Plastic Flow producing after yield limit, non-to large deformation situation effectChang Hao, is widely used in the world. The calculating of side slope stress field is the basic training of these computational methodsOne of can. FLAC3D can carry out the three-dimensional structure mechanical characteristic simulation of soil property, rock and other materialWith Plastic Flow analysis. Carry out the structure of matching reality by the polyhedron unit in adjustment three-dimensional grid. SingleUnit's material can adopt linearity or Non-linear constitutive model, under external force, and when material generation yield spreadAfter, grid can correspondingly deform and move (large deformation pattern). FLAC3D Explicit Lagrangian is calculatedMethod need not form stiffness matrix, therefore, just can solve large-scale three-dimensional ask based on less memory headroomTopic. Calculate side slope stress field, need to set up side slope FLAC computation model, must carry out following three sidesThe work of face: (1) is set up Finite Difference Meshes (2) and selected this structure characteristic and material character (3) that boundary condition is setWith primary condition. Complete after above-mentioned work, can obtain side slope initial balance stress state, namely limitStress of primary rock state before the excavation of slope. Then in software, carry out engineering excavation, calculate slope project and openStress field after digging.

A Slope physical efficiency described in step 2 resolves into a lot of particles, and particle is to every on the body of slopePut the least unit of carrying out mechanical analysis; Utilize Lagrangian finite difference method to carry out the stress field of side slopeWhen calculating, be not separately each particle to be calculated, because the quantity of particle is too huge, andBe in particle, to disperse to choose some nodes, node is exactly a part for particle, selecting in all particlesSome particles be defined as node. Then only these nodes are calculated, then by average, weighting orEtc. equivalent means, the stress field value of these nodes particle is around calculated.

Slope anchorage layout method of the present invention, compared with traditional method, obtains by the methodThe computing formula of the safety coefficient of particle in Slope body, by the value of safety factor value of each particle and stateThe safety coefficient of family's regulation and stipulation compares, and has just obtained carrying out the cloth office point of slope anchorage. The partyMethod has reduced blindly reinforces, and reduces construction investment, and the method is fully theoretical, and accuracy is good.

Brief description of the drawings

Fig. 1 is slope anchorage layout method schematic flow sheet of the present invention.

Fig. 2 is the Mohr-Coulomb's strength envelope figure described in the present invention.

Fig. 3 is the shear strength of rock τ in the present invention_cCalculate schematic diagram.

Fig. 4 is that on the Slope body in the present invention, each particle destroys minimum σ_3cIsogram

Fig. 5 is the safety coefficient K isogram of each particle on the Slope body in the present invention.

Fig. 6 is the safety coefficient design load K in the present invention₀=1.25 o'clock, the needs that Slope body destroys enteredThe isogram of the cloth office point of row slope anchorage.

Fig. 7 is the safety coefficient design load K in the present invention₀=1.25 o'clock, the required anchor force of Slope body etc.Value line chart.

Detailed description of the invention

Below in conjunction with accompanying drawing, the present invention is described in further detail, to make those skilled in the art's referenceDescription word can be implemented according to this.

The invention provides a kind of slope anchorage layout method, detailed description of the invention step is:

Step 1, in a side slope, gather three groups of cylindrical sample of rock mass in side slope, have 5 in every groupIndividual sample, the size of sample is diameter 50mm × high 80mm, then utilizes triaxial test to calculate respectively oftenThe following Mechanics Parameters of Rock Mass of group sample: elastic modelling quantity, Poisson's ratio, compression strength, cohesive strength and inAngle of friction, the Mechanics Parameters of Rock Mass value using the Mechanics Parameters of Rock Mass mean value of three groups of samples as this side slope;

Step 2, Slope body is decomposed into by particle and is formed, according to the above-mentioned elastic modelling quantity calculating,Poisson's ratio, compression strength, cohesive strength and internal friction angle parameter, utilize Lagrangian finite difference methodCarry out the stress field calculation of side slope, obtain the stress field value of each particle, and extract each matterThe maximum principal stress σ of point₁With minimum principal stress σ₃; According to the rock mass power of the side slope calculating in step 1The maximum master of each particle extracting in cohesive strength, internal friction angle parameter and step 2 in mathematic(al) parameterStress, minimum principal stress data can be drawn out the Mohr-Coulomb's intensity reason of each particle in Slope bodyOpinion figure, as shown in Figure 2, draws out the Mohr-Coulomb's strength theory figure of particle A and particle B. More-The mathematic(al) representation of coulomb strength theory is:

τ＝σtgφ+C(1)

Wherein, τ, σ, φ, C represents respectively shearing strength, the side slope rock of each particle in slope rock massInternal friction angle, rock in direct stress, Mechanics Parameters of Rock Mass value on the rock shearing face of each particle in bodyCohesive strength in mechanics parameter value.

Step 3, calculate each particle cause the destroyed minimum principal stress of this particle place side slope minimumValue, destroys minimum σ_3c, computational methods are as follows: σ_3c＝(σ₁-R_c)/tgθ², wherein, σ₁?Large principal stress, R_cThe compression strength in the Mechanics Parameters of Rock Mass value of this side slope,φ isInternal friction angle in the Mechanics Parameters of Rock Mass value of this side slope; Wherein, destroy minimum σ_3cComputational methods beDraw according to the existing achievement in research of forefathers. The described destroyed minimum master of particle place side slope that causes shouldPower minimum destroys minimum σ_3c, the whether destroyed maximum principal stress that depends on of the side slope at a particle placeσ₁With minimum principal stress σ₃Between difference, difference is larger, more easily cause destroy, therefore in maximumPrincipal stress σ₁The constant situation of value under, minimum principal stress σ₃Less, difference is larger, more easily causesThe side slope at this particle place is destroyed, therefore destroys minimum σ_3cJust refer in the situation that not occurring to destroyMinor principal stress σ₃The minimum of a value that can reach. As the σ of a particle in side slope₃Be less than it and destroy minimum σ_3cTime,Be σ₃＜σ_3cTime, this particle place side slope is just destroyed. As can be seen from Figure 2, particle A and particle BDestruction minimum σ_3cIt is respectively the destroyed minimum principal stress of side slope that causes particle A and particle B placeMinimum. According to the destruction minimum σ of particle in Slope body_3cComputational methods, every by what calculateThe destruction minimum σ of individual particle_3cDrawing isoline figure in data Input Software TECPLOT, as shown in Figure 4.

The σ that step 4, utilization calculate_3c, the shear strength of rock τ of each particle in calculating side slope_cRatio with the inner shear stress τ of slope bodyBe the safety coefficient K of each particle, computational methodsAs follows:

$K=\frac{{\mathrm{\σ}}_1-{\mathrm{\σ}}_{3c}}{{\mathrm{\σ}}_1-{\mathrm{\σ}}_3};$

Its derivation is:

(1) in side slope, the safety coefficient K of each particle is that the rock mass shearing resistance of each particle in side slope is strongThe ratio of degree and the inner shear stress of slope body:

$K=\frac{{\mathrm{\τ}}_c}{\mathrm{\τ}}---\left(2\right)$

(2)τ_cBe numerically equal to the length of vertical line AB in Fig. 3. τ thus_cCan be represented by following number:

${\mathrm{\τ}}_c=\frac{{\mathrm{\σ}}_1-{\mathrm{\σ}}_{3c}}{2}cos\mathrm{\φ}---\left(3\right)$

(3) in formula (3) substitution (2), the safety coefficient K of side slope can be expressed as:

$K=\frac{\frac{{\mathrm{\σ}}_1-{\mathrm{\σ}}_{3c}}{2}cos\mathrm{\φ}}{\mathrm{\τ}}---\left(4\right)$

(4) the denominator τ in formula (4) represents the shear stress of each particle in slope rock mass, according to notYou-coulomb theory, its mathematic(al) representation is:

$\mathrm{\τ}=\frac{{\mathrm{\σ}}_1-{\mathrm{\σ}}_3}{2}\sin 2\mathrm{\θ}---\left(5\right)$

Wherein, the shear surface that θ is each particle and the angle of biggest principal stress direction.

(5) the θ angle during due to particle generation failure by shear equalsTherefore cause in side slopeThe shear stress τ of particle failure by shear can be expressed as:

$\mathrm{\τ}=\frac{{\mathrm{\σ}}_1-{\mathrm{\σ}}_3}{2}\sin (\frac{\mathrm{\π}}{2}+\mathrm{\φ})=\frac{{\mathrm{\σ}}_1-{\mathrm{\σ}}_3}{2}cos\mathrm{\φ},(0\≤\mathrm{\φ}\≤\frac{\mathrm{\π}}{2})---\left(6\right)$

(6) by formula (6) substitution formula (4), the safety system of each particle in Slope bodyNumber K can further be written as:

$K=\frac{{\mathrm{\σ}}_1-{\mathrm{\σ}}_{3c}}{{\mathrm{\σ}}_1-{\mathrm{\σ}}_3}---\left(7\right)$

By the destruction minimum data σ of each particle_3cSubstitution formula (7), can calculate Slope bodyThe safety coefficient K of upper each particle. To calculate drafting equivalence in gained K data Input Software TECPLOTLine chart, as shown in Figure 5, the safety coefficient K isogram of each particle on Slope body.

Step 5, all safety coefficient K are less than to the particle of the safety coefficient design load that national regulation specifiesAs the cloth office point that need to carry out slope anchorage. The safety coefficient design load specifying when national regulationK₀=1.25, need to carry out the cloth office point of slope anchorage as shown in Figure 6.

Step 6, slope, opposite side slope, the cloth office point body that carries out as required slope anchorage carry out anchoring, under comprisingRow step:

(1), according to the border of the cloth office point that need to carry out slope anchorage described above, calculate Slope bodyThe degree of depth of anchoring;

(2) according to Side Slope Safety Coefficient design load K₀Requirement, carry out anchor force determine.

(3) in the slope body after anchoring, the safety coefficient K of each particle must be more than or equal to K₀。

(4), in formula (7), in side slope, the safety coefficient of each particle is:

$K=\frac{{\mathrm{\σ}}_1-{\mathrm{\σ}}_{3c}}{{\mathrm{\σ}}_1-{\mathrm{\σ}}_3}$

(5) due in natural Slope body, σ₁、σ_3cAll not modifiable quantitative, therefore,When the value of K is less than design load K₀Time, make the value of K reach design load K₀, just must improve σ₃'sValue. σ₃Value use engineering anchor measure to improve. σ₃The part that increases of value, be singlePlane amasss anchor force F.

So can there be following expression formula:

$\begin{array}{cc}{K}_0=\frac{{\mathrm{\&sigma;}}_1-{\mathrm{\&sigma;}}_{3c}}{{\mathrm{\&sigma;}}_1-({\mathrm{\&sigma;}}_3+F)}& (K<K_0)\end{array}---\left(8\right)$

(6) formula (8) and formula (7) are solved jointly, obtain unit are anchor force formula F as follows:

F＝(K₀-K)(σ₁-σ₃)/K₀(K＜K₀)(9)

According to the data of the safety coefficient K of Fig. 5, use formula (9), calculate side slope key area requiredThe unit are anchor force of wanting. To calculate drawing isoline figure in gained F data Input Software TECPLOT,As shown in Figure 7. Anchor force F is the key index in engineering reinforcement design, can, according to specification, directly useIn engineering anchor Design.

Although embodiment of the present invention are open as above, it is not restricted to description and enforcement sideListed utilization in formula, it can be applied to various applicable the field of the invention completely, for being familiar with abilityThe personnel in territory, can easily realize other amendment, therefore do not deviate from claim and etc. homotypeEnclose under limited universal, the present invention is not limited to specific details and illustrates here and the figure describingExample.

Claims (4)

1. a slope anchorage layout method, is characterized in that, comprises the following steps:

Step 1, in a side slope, gather many groups cylindrical sample of rock mass in side slope, many in every groupIn 3 samples, then utilize triaxial test to calculate respectively the following Mechanics Parameters of Rock Mass of every group of sample: bulletProperty modulus, Poisson's ratio, compression strength, cohesive strength and internal friction angle, will organize the rock mass mechanics of sample moreMean parameter is as the Mechanics Parameters of Rock Mass value of this side slope;

Step 2, Slope body is decomposed into by particle and is formed, according to the above-mentioned elastic modelling quantity calculating,Poisson's ratio, compression strength, cohesive strength and internal friction angle parameter, utilize Lagrangian finite difference methodCarry out the stress field calculation of side slope, obtain the stress field value of each particle, and extract each matterThe maximum principal stress σ of point₁With minimum principal stress σ₃；

Step 3, calculate each particle cause the destroyed minimum principal stress of this particle place side slope minimumValue, destroys minimum σ_3c, computational methods are as follows: σ_3c＝(σ₁-R_c)/tgθ², wherein, σ₁?Large principal stress, R_cThe compression strength in the Mechanics Parameters of Rock Mass value of this side slope,φ isInternal friction angle in the Mechanics Parameters of Rock Mass value of this side slope;

The σ that step 4, utilization calculate_3c, the shear strength of rock τ of each particle in calculating side slope_cRatio with the inner shear stress τ of slope bodyBe the safety coefficient K of each particle, computational methodsAs follows:

$K=\frac{{\mathrm{\&sigma;}}_1-{\mathrm{\&sigma;}}_{3c}}{{\mathrm{\&sigma;}}_1-{\mathrm{\&sigma;}}_3};$

Step 5, all safety coefficient K are less than to the particle of the safety coefficient design load that national regulation specifiesAs the cloth office point that need to carry out slope anchorage.

2. slope anchorage layout method as claimed in claim 1, is characterized in that, in described step 1While gathering the cylindrical sample of rock mass in side slope, can gather 3 groups of samples, the sample size in every group is5.

3. slope anchorage layout method as claimed in claim 2, is characterized in that, according in step 1In cohesive strength, internal friction angle parameter and step 2 in the Mechanics Parameters of Rock Mass of the side slope calculating, extractThe maximum principal stress of each particle going out, More-Ku that minimum principal stress data are drawn out each particleHuman relations strength theory figure, according to Mohr-Coulomb's strength theory figure, the rock mass that calculates each particle in side slope is anti-Cut intensity τ_cWith the inner shear stress τ of slope body, computational methods are as follows: θ is the shear surface of each particle and the angle of biggest principal stress direction,Can calculate thus the safety coefficient K of each particle.

4. slope anchorage layout method as claimed in claim 1, is characterized in that, also comprise step 6,Carry out anchoring according to slope, opposite side slope, the cloth office point body that need to carry out slope anchorage obtaining in step 5, compriseThe following step: (1), according to the border of the cloth office point that need to carry out slope anchorage described above, calculates limitThe degree of depth of slope, slope body anchoring; (2) needed while carrying out anchoring to carrying out the cloth office point of slope anchorageUnit are anchor force F calculates, and computational methods are as follows: F=(K₀-K)(σ₁-σ₃)/K₀(K＜K₀)，Wherein, K₀The safety coefficient design load specifying for national regulation.