CN106650118A - Optimization design method for governing parameters of side slope slide-resistant pile - Google Patents

Abstract

The invention belongs to the technical field of landslide prevention and control, and particularly relates to an optimization design method for governing parameters of a side slope slide-resistant pile. Which comprises the following steps: determining physical and mechanical parameters of a side slope soil layer; determining design parameters of the anti-slide pile and analyzing stress; determining the maximum lateral pressure value of the soil layer of the embedded section by an m method; determining an optimal coefficient of pile position spacing; determining the optimal pile position spacing; and (4) optimizing and calculating the internal force calculation parameters of the slide-resistant pile. The method supplements and corrects uncertainty of the traditional slide-resistant pile calculation parameters selected in a large area, and provides a new method which breaks through the existing method, is easy to calculate and has strong applicability, so that double optimization of the slide-resistant pile on two layers of pile arrangement and calculation is realized. Practice proves that the distance determined by the method is within a value range specified by a specification and is accurate to a certain value, and the purpose of parameter optimization is achieved.

Description

A kind of Anti-sliding Pile administers the Optimization Design of parameter

Technical field

The invention belongs to preventing land slide technical field, and in particular to a kind of Anti-sliding Pile administers the optimization design side of parameter Method.

Background technology

The fast-developing and infrastructure construction demand of current economic construction is growing, promotes increasing industry With the construction of the main facilities such as civil building engineering, hydraulic engineering, municipal works, road engineering and science of bridge building, substantial amounts of side Slope engineering and its estimation of stability problem have become engineering construction field focus of attention.At the same time, substantial amounts of engineering is built If also promoting landslide control technical measures to obtain corresponding perfect and development, more Treatment process are controlled on landslide with measure Reason field played an important role.Wherein, friction pile is also widely applied as one of important landslide control technical measures Among landslide control engineering practice.

Friction pile is the pile that slider bed is penetrated with through gliding mass, to slope reinforcement, a gear for resisting gliding mass downslide power Structure, plays stable side slope, is the major measure that a kind of side slope antiskid is processed.The mechanism of action of friction pile is using anchoring Section balances the Thrust of slopes in the anchorage effect and passive resisting force of good ground.Contrast soil nailing anchor pole, antiskid retaining wall etc. Other landslide control measures, friction pile mainly has the advantage that：1. antiskid is functional, pile bending resistance itself and shear stiffness Greatly, very big Thrust can be resisted；2. construction safety performance is strong, constructs little to the range of disturbance of surrounding formation, is difficult to deteriorate Landslide state, can be used to salvage；3. bricklaying quantity is little, harnessing project low cost, economical rationality；4. further can examine ground Matter condition, the former design of amendment in time；5. can flexibly coordinate with other slope treatment measures such as soil nailing, anchor pole.Due to anti- Sliding pile is in harnessing landslide and safeguards outstanding advantages on stability of slope, makes friction pile be widely used in mine slope, railway, highway In the slope project such as landslide, industrial and civil buildings pattern foundation pit supporting structure, harbour, thus how anti-slide pile controlling parameter is optimized Design and construction, the especially importance of the optimization design of friction pile pile spacing are highlighted further, and become anti-slide pile design with The important key issue that construction field faced and solved.

Important indicator when pile spacing is anti-slide pile design, pile spacing is excessive to be likely to result in AsA -GSH cycle failure, Pile spacing is too small and easily causes investment increase, so rational optimum pile spacing is a weight in anti-slide pile controlling engineering practice The design parameter wanted.The main stream approach for determining friction pile superior distance at present is soil arching effect analytic approach under different assumed conditions. The method is in side slope engineering between friction pile on the basis of soil arching effect analysis, proposition should with static balance condition between stake, Cross-sectional strength condition co- controlling is determining pile spacing at spaning middle section strength condition and arch springing.But the method is not accounted for Anti-Slide Pile Internal Force distribution occasion and deformation compatibility condition, there is significant limitation.

The content of the invention

For supplementary limitation and deficiency with the above-mentioned traditional friction pile of amendment in terms of design parameter accuracy is selected, this It is bright to seek to a kind of existing tradition of breakthrough, be easy to calculate and pervasive new method, to realize that friction pile is being laid out pile and calculated Two aspect double optimizations, reaching carries out science, effective management goal to landslide disaster.

The present invention is realized using following technical scheme：

A kind of Anti-sliding Pile administers the Optimization Design of parameter, comprises the following steps：

Step one：The determination of side slope soil layer physical and mechanical parameter；

Step 2：The determination of anti-slide pile design parameter and force analysis；

Step 3：" m " method determines fixed section soil layer maximum lateral pressure value；

Step 4：The determination of stake column pitch optimal coefficient；

Step 5：The determination of optimum stake column pitch；

Step 6：The optimization of anti-slide pile internal force calculation parameter is calculated.

In the step one, according to《Slope project geotechnical investigation code》(YS5230-1996) and《Earthwork test rule》 (SL237-1999) carry out prospecting, test and the survey and drawing of investigation of system to side slope to be determined, with ground in-situ test or room Interior soil test synthesis measuring side slope slopes soil layer physical and mechanical parameter (c,γ).And according to《Landslide control engineering is designed With construction technique normalizing》(DZ/T 0219-2006) " appendix C " tables look-up and determines subgrade soil ratio coefficient m.

The step 2 includes：

1) determination of anti-slide pile design parameter

In order that gliding mass has enough stability between stake, will not extrude between stake under sliding force effect, and between stake Frictional resistance produced by the soil body and two sides is not less than the Thrust of Landslide between stake, between the horizontal layout of stake should meet suitably Away from；Suitable building-in depth and stake is long can ensure that friction pile is delivered to the side wall stress on stratum below sliding surface and is not more than stratum Laterally allow compression strength.According to《Landslide control engineering technique of design and construction specification》(DZ/T 0219-2006), with reference to Mentioned above principle, engineering geological data and design requirement, it is determined that load-bearing segment length h of stake₁, build-in segment length h₂。

2) determination of gross thrust suffered by friction pile

The design load of friction pile is mainly as follows：1. the Thrust of Landslide that single pile bears, acts on the stake of sliding surface above section Back, it may be assumed that parallel with sliding surface；2. passive earth pressure before stake.Commonly assume that Thrust of Landslide that every pile born and broken ground The difference of pressure is equal to Thrust of Landslide of the pile center within the scope of：

P=P_T-E_p (1)

In formula, gross thrust suffered by P- friction piles, i.e. friction pile total skid resistance (kN)；P_TThrust of Landslide (kN) before-stake (should be by The corresponding computing formula of different sliding surface type selectings determines, is specifically shown in《Landslide control engineering technique of design and construction specification》 " appendix A ")；E_pPassive earth pressure (kN) before-stake.

In the step 3, fixed section soil layer maximum lateral pressure value ensures that pile safety, normal work allow to hold The maximum stress value received, when friction pile working stress is less than the value, the pile is safe, while being also that friction pile optimum sets Master data in meter parameter determination process.The difference of structure, construction and mechanical property according to friction pile place soil layer, build-in Section soil layer maximum lateral pressure value can be by specification《Landslide control engineering technique of design and construction specification》(DZ/T 0219—2006) In following (2) (3) formula obtain：

1) more complete rock mass or flint clay rock

σ_max=ρ₁·R (2)

2) the general soil body or the broken rock of serious weathering

σ_max=ρ₂·(σ_p-σ_a) (3)

In formula, σ_max- fixed section soil layer maximum lateral pressure value (kPa)；ρ₁- reduction coefficient, depending on Rock And Soil crack, Weathering and softening degree, otherness in the horizontal direction etc., generally 0.1～0.5；ρ₂- reduction coefficient, depending on soil structures The precision of feature and mechanical strength parameter, suitable value is 0.5～1.0；R- Rock Under Uniaxial Compression ultimate compressive strengths (kPa)；σ_pBefore-stake Rock And Soil acts on the passive soil compressive stress (kPa) of pile body；σ_aRock And Soil acts on the active soil compressive stress of pile body after-stake (kPa)。

In the step 4, M is defined_sFor stake column pitch optimal coefficient, effect of the friction pile in unit Thrust is represented The stress of lower generation, is determined by formula (4) (5)：

So that stake bottom is reduced to free end as an example,

In formula, M_s- stake column pitch optimal coefficient；M- subgrade soil ratio coefficient (kN/m⁴), by《Landslide control engineering is designed and applied Work technical specification》(DZ/T 0219-2006) " appendix C " tables look-up determination；E- friction pile elastic modelling quantity (MPa)；The deformation of α-stake Coefficient (m^-1),B_PWidth, rectangular pile B are calculated for stake front_P=B+1, circular stake B_P=0.9 × (B+1), B is stake cross-sectional width or diameter；I- stake cross sectional moment of inertia (m⁴)；A_i、B_i、C_i、D_i- i ∈ [Isosorbide-5-Nitrae], with the conversion depth of stake The influence function value of different m methods (is tabled look-up and is tried to achieve, table is shown in《Highway bridge and culvert ground and foundation design code》(JTG D63—2007) Table is P.0.8), wherein band subscript h₂Represent pile bottom values.

In the step 5, on the premise of antiskid structure safety and stability is ensured, to avoid the waste in designing, shortening from applying The work duration, to reach balance of the safety of structure with economic rationality and coordination, in long equal, the sectional dimension identical condition of stake Under, the superior distance of adjacent two positions can be determined by formula (6)：

In formula, s_op- adjacent two position superior distances；σ_max- soil layer maximum lateral pressure value (kPa)；K_s- safety coefficient, takes Value is shown in《Slope project geotechnical investigation code》Values of the table 8.1.3 with regard to stability factor of slope in (YS5230-1996)；P- antiskids Stake suffered gross thrust, i.e. friction pile total skid resistance (kN).

In the step 6, after optimum stake column pitch determines, you can carry out the optimization meter of pile internal force calculating parameter Calculate (concrete derivation sees its general principles 2)：

In formula, M_y、Q_yThe moment of flexure (kNm) in the arbitrary section of-anchoring section pile body, shearing (kN)；x_A、φ_A、M_A、Q_A- sliding surface The displacement (m) of place's stake, corner (rad), moment of flexure (kNm) is sheared (kN).When stake bottom is free end, M_A、Q_A、x_A、φ_ABy formula (8) try to achieve：

The theoretical foundation of the inventive method is as follows：

The optimum column pitch of principle 1 and Optimal calculation Width Formula of Rib Knitted Fabric are derived

Order

Then pile body lateral stress is represented by

According to code requirement, σ_y≤σ_max, take limiting condition σ_y=σ_max, by position of fixity internal force diagram σ_yScheme to be understood (see Fig. 3), Work as y=h₂When, σ_yReach maximum, i.e. σ_y=σ_max, therefore byObtain final product formula (3)

Wherein, ν=ζ_xA₁+ζ_φB₁+C₁, u=ξ_xA₁+ξ_φB₁+D₁, then

Define M_sFor stake column pitch optimal coefficient,And according to《Slope project prospecting rule Model》Table 8.1.3 determines the safety coefficient K of a miniature clump of piles with regard to the value of stability factor of slope in (YS 5230-1996)_s, Certain safety stock is given to miniature clump of piles estimation of stability, optimum stake column pitch can be finally obtained

Principle 2 " m " method calculates Anti-Slide Pile Internal Force

The deformation of elastic pile includes shift in position and the flexural deformation of pile body itself, in " m " method, the deformation coefficient of stakeWhen, stake top (anchoring section) is by the curve differential equation of horizontal loading

In formula, myB_PX- grounds act on the horizontal resist forces in stake, and for " m " method, above-mentioned curve differential equation is to anchoring The condition of Duan Chengli is the coefficient of subgrade reaction zero at sliding surface.

This is Fourth Order Linear variable coefficient homogeneous differential equation, with approximate solution is carried out after power series expansion, is converted after arranging

In formula：x_y、M_y、Q_yThe displacement (m) in the arbitrary section of-anchoring section pile body, moment of flexure (kNm) is sheared (kN)；x_A、φ_A、 M_A、Q_AThe displacement (m) of stake at-sliding surface, corner (rad), moment of flexure (kNm) is sheared (kN)；A_i、B_i、C_i、D_i- i ∈ [Isosorbide-5-Nitrae], With the conversion depth of stake, the influence function value of different m methods (is tabled look-up and is tried to achieve, table is shown in《Highway bridge and culvert ground and foundation design code》 (JTG D63-2007) table is P.0.8), wherein band subscript h₂Represent pile bottom values.

Above formula is the general formulae of " m " method, and the x at sliding surface must be first tried to achieve during calculating_AAnd φ_A, can just seek arbitrary section of pile body Lateral stress of the displacement, corner, moment of flexure, shearing and foundation soil in face to the section.For this reason, it may be necessary to be reduced to freedom according to post bottom The determination of end, hinge support and the arbitrary boundary conditions of fixing end three, the now explanation by taking the free end of post bottom as an example.

When stake bottom is free end, M_B=0, Q_B=0, φ_B≠0、x_B≠ 0, by M_B=0, Q_B=0 substitutes into the 3rd, the 4 of formula (7) Formula, connection is solved

By corresponding x under above-mentioned each arbitrary boundary conditions_AAnd φ_ASubstitution formula (9), you can try to achieve the following pile body of sliding surface arbitrary The displacement in section and internal force.

The method that the present invention is adopted is to take the stake under Thrust and resistant force in front of anti-sliding pile effect of internal force limiting condition, i.e. friction pile The maximum stress that post is produced is equal to and the maximum lateral pressure value for determining is calculated by the parameter of pile body place soil layer, enters from Internal forces Hand reversely derives its design parameter, and then determines the superior distance of friction pile.The method is supplemented and have modified traditional friction pile meter Calculate the uncertainty that parameter is selected on big interval, it is proposed that a kind of breakthrough existing method, be easy to calculate and strong applicability it is new Method, to realize laying out pile and calculating two aspect double optimizations to friction pile.It was verified that the spacing that the method determines is in rule It is in the span of model defined and accurate in a certain value, realize the purpose of parameter optimization.

Description of the drawings

Fig. 1 flow charts of the present invention；

Fig. 2 anti-slide pile design load schematic diagrames；

Fig. 3 friction pile anchoring section stress envelopes.

Specific embodiment

Certain engineering is located at certain road K9+590～K10+010 road section surfaces right side side slope.Jing engineering geological investigations, the region is rugged Rugged, narrow mountain region, construction environment is severe, and big machinery machine-team turnover difficulty is big, and stratum soil property is loose, and sensitivity is high.Jing Comprehensive test is crossed, is suitably laid out pile method using a miniature clump of piles proposed by the invention at this.Come in addition detailed with reference to the engineering Its feasibility is discussed, to illustrate its practical significance and value.Specific implementation step is as follows：

Step one：The determination of landslide soil layer physical and mechanical parameter

By《Slope project geotechnical investigation code》(YS5230-1996) and《Earthwork test rule》(SL237-1999) are to be measured Fixed side slope carries out prospecting, test and the survey and drawing of investigation of system, with ground in-situ test or laboratory soil test synthesis measuring Side slope slopes soil layer physical and mechanical parameter (c,γ).And according to《Landslide control engineering technique of design and construction specification》 (DZ/T 0219-2006) " appendix C " tables look-up and determines subgrade soil ratio coefficient m, refers to table 1.

The slopes design parameter of table 1

Step 2：The determination of anti-slide pile design parameter and force analysis

1) determination of anti-slide pile design parameter

In order that gliding mass has enough stability between stake, under sliding force effect, will not extrude between stake, and between stake Frictional resistance produced by the soil body and two sides is not less than the Thrust of Landslide between stake, between the horizontal layout of stake should meet suitably Away from；Suitable anchorage depth and stake is long can ensure that friction pile is delivered to the side wall stress on stratum below sliding surface and is not more than stratum Laterally allow compression strength.

According to《Landslide control engineering technique of design and construction specification》In, with reference to mentioned above principle, engineering geological data and set Meter requires to determine that the horizontal layout of stake, pile spacing, stake be long and anchoring depth, is specifically shown in Table 2.

The design parameter that table is 2

2) determination of gross thrust suffered by friction pile

The design load (stress diagram is shown in Fig. 2) of friction pile is main as follows：1. the Thrust of Landslide that single pile bears, acts on The stake back of sliding surface above section, it may be assumed that parallel with sliding surface；2. passive earth pressure before stake.Commonly assume that what every pile was born The difference of Thrust of Landslide and passive earth pressure is equal to Thrust of Landslide of the pile center within the scope of：

P=P_T-E_p=4000-3889.23=110.77kN/m (1)

In formula, gross thrust suffered by P- friction piles, i.e. friction pile total skid resistance (kN)；P_TThrust of Landslide (kN) before-stake (should be by The corresponding computing formula of different sliding surface type selectings determines, is specifically shown in《Landslide control engineering technique of design and construction specification》 " appendix A "), calculation procedure is complicated, omits herein；E_pPassive earth pressure (kN) before-stake.

Step 3：" m " method determines fixed section soil layer maximum lateral pressure value

Fixed section soil layer maximum lateral pressure value ensures pile safety, normal work institute maximum stress allowed to bear Value, when friction pile working stress is less than the value, the pile is safe, while being also basic in optimized parameter determination process Data.The difference of structure, construction and mechanical property according to friction pile place soil layer, fixed section soil layer maximum lateral pressure value can By specification《Landslide control engineering technique of design and construction specification》Formula (2) (3) in (DZ/T 0219-2006) is obtained：

In formula, σ_max- fixed section soil layer maximum lateral pressure value (kPa)；ρ₂- reduction coefficient, depending on soil structures feature With the precision of mechanical strength parameter, suitable value is 0.5～1.0；σ_pRock And Soil acts on the passive soil compressive stress of pile body before-stake (kPa)；σ_aRock And Soil acts on the active soil compressive stress (kPa) of pile body after-stake.

Step 4：The determination of stake column pitch optimal coefficient

Define M_sFor stake column pitch optimal coefficient, what the miniature clump of piles of expression was produced in the presence of unit Thrust answers Power, is determined by formula (4) (5)：

So that stake bottom is reduced to free end as an example,

In formula, M_s- stake column pitch optimal coefficient；M- subgrade soil ratio coefficient (kN/m⁴), by《Landslide control engineering is designed and applied Work technical specification》(DZ/T 0219-2006) " appendix C " tables look-up determination；E- friction pile elastic modelling quantity (MPa)；The deformation of α-stake Coefficient (m^-1),B_PWidth, rectangular pile B are calculated for stake front_P=B+1, circular stake B_P=0.9 × (B+1), B is stake cross-sectional width or diameter；I- stake cross sectional moment of inertia (m⁴)；A_i、B_i、C_i、D_i- i ∈ [Isosorbide-5-Nitrae], with the conversion depth of stake The influence function value of different m methods (is tabled look-up and is tried to achieve, table is shown in《Highway bridge and culvert ground and foundation design code》(JTG D63—2007) Table is P.0.8), wherein band subscript h₂Represent pile bottom values.

Step 5：The determination of optimum stake column pitch

On the premise of antiskid structure safety and stability is ensured, to avoid the waste in designing, shorten the construction period, to reach Balance and coordination of the safety of structure with economic rationality, under the conditions of long equal, the sectional dimension identical of stake, can be by formula (6) superior distance of adjacent two positions is determined：

In formula, s_op- adjacent two position superior distances；σ_max- soil layer allows lateral pressure；K_s- safety coefficient, value is shown in《Side slope Engineering investigation specification》With regard to the value of stability factor of slope, this example takes 1.05 to table 8.1.3 in (YS5230-1996)；P- resists Gross thrust suffered by sliding pile, i.e. friction pile total skid resistance (kN).

Step 6：The optimization of anti-slide pile internal force calculation parameter is calculated

The excellent of pile internal force calculating parameter can be carried out after optimum stake column pitch and section Optimal calculation width determine Change and calculate：

In formula：M_y、Q_yThe moment of flexure (kNm) in the arbitrary section of-anchoring section pile body, shearing (kN)；x_A、φ_A、M_A、Q_A- sliding surface The displacement (m) of place's stake, corner (rad), moment of flexure (kNm) is sheared (kN).When stake bottom is free end, M_A、Q_A、x_A、φ_ABy formula (8) try to achieve：

The internal force result of calculation of table 3

Claims (7)

1. a kind of Anti-sliding Pile administers the Optimization Design of parameter, it is characterised in that comprise the following steps：

Step one：The determination of side slope soil layer physical and mechanical parameter；

Step 2：The determination of anti-slide pile design parameter and force analysis；

Step 3：" m " method determines fixed section soil layer maximum lateral pressure value；

Step 4：The determination of stake column pitch optimal coefficient；

Step 5：The determination of optimum stake column pitch；

Step 6：The optimization of anti-slide pile internal force calculation parameter is calculated.

2. a kind of Anti-sliding Pile according to claim 1 administers the Optimization Design of parameter, it is characterised in that described In step one determine side slope slopes soil layer physical and mechanical parameter c,γ, and determine subgrade soil ratio coefficient m.

3. a kind of Anti-sliding Pile according to claim 2 administers the Optimization Design of parameter, it is characterised in that described Step 2 includes：

1) determination of anti-slide pile design parameter

It is determined that load-bearing segment length h of stake₁, build-in segment length h₂；

2) determination of gross thrust suffered by friction pile

It is assumed that the difference of the Thrust of Landslide born per pile and passive earth pressure is equal to Thrust of Landslide of the pile center within the scope of：

P=P_T-E_p (1)

In formula, the total skid resistance of gross thrust suffered by P- friction piles, i.e. friction pile, kN；P_TThrust of Landslide before-stake, kN；E_pIt is passive before-stake Soil pressure, kN.

4. a kind of Anti-sliding Pile according to claim 3 administers the Optimization Design of parameter, it is characterised in that described Fixed section soil layer maximum lateral pressure value is obtained by following (2) (3) formula in step 3：

1) more complete rock mass or flint clay rock

σ_max=ρ₁·R (2)

2) the general soil body or the broken rock of serious weathering

σ_max=ρ₂·(σ_p-σ_a) (3)

In formula, σ_max- fixed section soil layer maximum lateral pressure value, kPa；ρ₁- reduction coefficient, value is 0.1～0.5；ρ₂- reduction system Number, value is 0.5～1.0；R- Rock Under Uniaxial Compression ultimate compressive strengths, kPa；σ_pRock And Soil acts on being broken ground for pile body before-stake Compression, kPa；σ_aRock And Soil acts on the active soil compressive stress of pile body, kPa after-stake.

5. a kind of Anti-sliding Pile according to claim 4 administers the Optimization Design of parameter, it is characterised in that described Stake column pitch optimal coefficient M in step 4_sDetermined by formula (4) (5)：

$M_s=\frac{{\mathrm{mh}}_2}{{\mathrm{\α}}^{2}EI}(\frac{h_{1}v}{3}+\frac{u}{\mathrm{\α}})---\left(4\right)$

When stake bottom is reduced to free end,

$\left\{\begin{array}{c}v=\frac{B_3^{h_2}{C}_4^{h_2}-C_3^{h_2}{B}_4^{h_2}}{A_3{B}_4-B_3{A}_4}\·A_1^{h_2}+\frac{C_3^{h_2}{A}_4^{h_2}-A_3^{h_2}{C}_4^{h_2}}{A_3{B}_4-B_3{A}_4}\·B_1^{h_2}+C_1^{h_2}\\ u=\frac{B_3^{h_2}{D}_4^{h_2}-D_3^{h_2}{B}_4^{h_2}}{A_3^{h_2}{B}_4^{h_2}-B_3^{h_2}{A}_4^{h_2}}\·A_1^{h_2}+\frac{D_3^{h_2}{A}_4^{h_2}-A_3^{h_2}{D}_4^{h_2}}{A_3^{h_2}{B}_4^{h_2}-B_3^{h_2}{A}_4^{h_2}}\·B_1^{h_2}+D_1^{h_2}\end{array}\right.---\left(5\right)$

In formula, M_s- stake column pitch optimal coefficient；M- subgrade soil ratio coefficients, kN/m⁴；E- friction pile elastic modelling quantity, MPa；α-stake Deformation coefficient, m^-1,B_PWidth, rectangular pile B are calculated for stake front_P=B+1, circular stake B_P=0.9 × (B+ 1), B is stake cross-sectional width or diameter；I- stake cross sectional moment of inertias, m⁴；A_i、B_i、C_i、D_i- i ∈ [Isosorbide-5-Nitrae], with the conversion depth of stake And the influence function value of different m methods, wherein band subscript h₂Represent pile bottom values.

6. a kind of Anti-sliding Pile according to claim 5 administers the Optimization Design of parameter, it is characterised in that described In step 5 under the conditions of long equal, the sectional dimension identical of stake, the superior distance of adjacent two positions is determined by formula (6)：

$s_{op}=\frac{{\mathrm{\σ}}_{max}}{K_s{M}_{s}P}---\left(6\right)$

In formula, s_op- adjacent two position superior distances, m；K_s- safety coefficient；Gross thrust suffered by P- friction piles, i.e. friction pile always resist Sliding power, kN.

7. a kind of Anti-sliding Pile according to claim 6 administers the Optimization Design of parameter, it is characterised in that described The optimization of step 6 pile post internal force calculating parameter is calculated as follows：

$\left\{\begin{array}{c}{M}_y={\mathrm{\α}}^{2}EI\left(x_A{A}_3+\frac{{\mathrm{\φ}}_A}{\mathrm{\α}}{B}_3+\frac{M_A}{{\mathrm{\α}}^{2}EI}{C}_3+\frac{Q_A}{{\mathrm{\α}}^{3}EI}{D}_3\right)\\ Q_y={\mathrm{\α}}^{3}EI\left(x_A{A}_4+\frac{{\mathrm{\φ}}_A}{\mathrm{\α}}{B}_4+\frac{M_A}{{\mathrm{\α}}^{2}EI}{C}_4+\frac{Q_A}{{\mathrm{\α}}^{3}EI}{D}_4\right)\end{array}\right.---\left(7\right)$

In formula, M_y、Q_yThe moment of flexure in the arbitrary section of-anchoring section pile body, kNm, shearing, kN；x_A、φ_A、M_A、Q_AStake at-sliding surface Displacement, m, corner, rad, moment of flexure, kNm, shearing, kN；

When stake bottom is free end, M_A、Q_A、x_A、φ_ATried to achieve by formula (8)：

$\left\{\begin{array}{c}{M}_A=\frac{1}{3}{\mathrm{Ps}}_{op}{h}_1\\ Q_A={\mathrm{Ps}}_{op}\\ x_A=\frac{M_A}{{\mathrm{\α}}^{2}EI}\·\frac{B_3{C}_4-C_3{B}_4}{A_3{B}_4-B_3{A}_4}+\frac{Q_A}{{\mathrm{\α}}^{3}EI}\·\frac{B_3{D}_4-D_3{B}_4}{A_3{B}_4-B_3{A}_4}\\ {\mathrm{\φ}}_A=\frac{M_A}{\mathrm{\α}EI}\·\frac{A_4{C}_3-C_4{A}_3}{A_3{B}_4-B_3{A}_4}+\frac{Q_A}{{\mathrm{\α}}^{2}EI}\·\frac{A_4{D}_3-D_4{A}_3}{A_3{B}_4-B_3{A}_4}\end{array}\right.---\left(8\right).$