CN104268365B - Critical excavation length determining method of thick sand layer gentle slope inclined shaft surface excavation method and sub-surface excavation method - Google Patents

Abstract

The invention discloses a critical excavation length determining method of a thick sand layer gentle slope inclined shaft open excavation method and a sub-surface excavation method. The method is characterized in that open channel excavation length is calculated according to inclined shaft inclination angle, ground gradient, open channel side slope gradient, shaft excavation height, top plate safety thickness and plowing layer thickness; inclined shaft excavation grading angle and excavation inclination length are used as variable parameters to respectively calculate to obtain the building cost functions of each of the open excavation method and the sub-surface excavation method; the critical excavation length of inclined shaft open excavation and sub-surface excavation is determined by analyzing different design parameter indexes and comparing and analyzing the building cost functions. The method has the advantages that the critical excavation length of the open excavation method and the subsurface excavation method is determined from angles such as engineering mechanics and project building cost, project safety requirements can be satisfied, project building cost is effectively controlled at the same time, project benefits are increased, and theoretical basis is provided for determining the critical excavation length of the thick sand layer gentle slope inclined shaft open excavation method and the sub-surface excavation method.

Description

The critical length determining method of thick sand bed gentle slope inclined shaft cut and cover method and subsurface excavation method

Technical field

The present invention relates to coal mine inclined shaft pit shaft is built.Specifically related to thick sand bed gentle slope inclined shaft cut and cover method is critical with subsurface excavation method Excavation length determines method.

Background technology

When carrying out shaft construction using common law, slope mouth digging mode is divided into flume and dark cave, except utilizing in mountain area Stable slope terrain directly carries out dark cave and excavates outer, is typically both needed to adopt trench excavation, and to overcome, well head coating is thin, soil property The difficulty of soft, top board not easy care.At present the determination of trench excavation length and flume slope angle is mainly according to engineering experience Obtain with engineering analog method, lack certain theoretical foundation.For this present situation, the present invention is by different designs parameter index point Analysis and Cost Function relative analyses, the critical for being capable of more scientific rational determination gentle slope inclined shaft cut and cover method and subsurface excavation method is long Degree, the value for the parameter provides certain scientific basis.

The content of the invention

It is an object of the invention to provide one kind is with oblique way slope angle and excavates plagioclase as variable parameter, calculate respectively The Cost Function and direct cost of cut and cover method and subsurface excavation method are drawn, determines rich water thick sand bed gentle slope inclined shaft cut and cover method with subsurface excavation method Critical length determining method.

The critical length of cut and cover method and subsurface excavation method when inclined shaft is built can not be scientifically and rationally calculated for existing theory, The technical scheme is that such solution：

First, trench excavation length ideal determines method

(1), trench excavation size determines

1., flume slant height H：

In formula：α-inclined shaft inclination angle；α '-ground line gradient；α₁- bright groove grade of side slope；H_Pick- shaft excavation height；h₁- top Plate safe thickness；h₂- arable layer thickness.

2., slot bottom width B₁：B₁=B+0.6

In formula：B-flume shaft excavation width

3., flume width B suitable for reading₂：

B₂=B₁+2H sinα₁

4., flume length L suitable for reading：

5., flume bottom length l：

6., total amount of excavation V_Dig：

7., wellbore volume V_{Pit shaft}：

S-flume section shaft excavation cross-sectional area.

8., earth volume V is backfilled_{Fill out}：

V_{Fill out}=V_Dig-V_{Pit shaft}

(2), flume length determines

In critical gradient α₀Under, flume bottom length is determined by below equation：

Flume slant height：

Flume bottom is long：

2nd, the cost of trench excavation length determines method

(1), the foundation of cut and cover method excavation length object function

By consulting《Coal builds well lane engineering cost consumption amount quota》(base price in 2007) understands, slope mouth flume Various native base prices and retaining portion price are excavated, it is known that the excavation and filling earth volume that can be calculated according to above formula, calculates open cut Method flume part total cost, need to consider slope mouth trench excavation gravel soil, backfill expense during calculating；Reinforcing bar colligation；Ground Slabstone mortar expense；

(2), the determination of subsurface excavation method excavation length object function

During due to shallow mining method, it is not necessary to carry out large-scale earthwork excavation and filling, therefore when its construction costs is calculated, only need Consider the driving of inclines and the consuming of supporting；

(3), contrast determines flume length

In summary, the cost of trench excavation and bright groove grade of side slope α₁L long with flume bottom is relevant, and during shallow mining method Also l long with flume bottom land is relevant, and with excavation length as independent variable, construction costs is dependent variable, is done according to the Cost Function set up Go out light and dark digging cost contrast curve, open cut cost as adopts bright with corresponding l values during flume cost equal length in figure The flume segment length marginal value of digging method construction.

The present invention compared with prior art, invention introduces the concept of critical gradient, at utmost using the soil body from Steady feature, while to cut and cover method and subsurface excavation method respectively from engineering mechanics and Analysis of Engineering Construction Cost.Being capable of more section through relative analyses Learn the rational critical length for determining gentle slope inclined shaft cut and cover method and subsurface excavation method.

Description of the drawings

Light and dark digging cost contrast curve when Fig. 1 is 56.5 ° of critical gradient；

Light and dark digging cost contrast curve when Fig. 2 is 44.6 ° of critical gradient.

Specific embodiment

The content of the invention is described further with reference to the accompanying drawings and detailed description：

Embodiment 1

First, trench excavation length ideal determines method

(1), trench excavation size determines

1., flume slant height H：

In formula：α-inclined shaft inclination angle；Take α=5.5 °；α '-ground line gradient；Take 0 °；α₁- bright groove grade of side slope；H_Pick- well Cylinder driving height, takes 5.35m；h₁- Roof safety thickness, takes 3m；h₂- arable layer thickness, takes 0.3m.

2., slot bottom width B₁：B₁=B+0.6

In formula：- flume shaft excavation width；6.5m is taken, then

B₁=7.1m

3., flume width B suitable for reading₂：

B₂=B₁+2H sinα₁=7.1+2H sin α₁

4., flume length L suitable for reading：

5., flume bottom length l：

6., total amount of excavation V_Dig：

7., wellbore volume V_{Pit shaft}：

S-flume section shaft excavation cross-sectional area；It is taken as 30.24m²。

8., earth volume V is backfilled_{Fill out}：

(2), flume length determines

Because flume bottom length is relevant with flume sloping coefficient, theoretical according to Analysis of Slope Stability, side slope is native in the engineering Matter is sand, cohesion C=10.0KPa, by internal friction angleAnd Kmin=1.30, obtaining critical gradient is：α=56.5 °

Therefore under critical gradient, flume bottom length is determined by below equation：

Flume slant height：

Flume bottom is long：

2nd, the cost of trench excavation length determines method

(1), the foundation of cut and cover method excavation length object function

According to the excavation and filling earth volume that above formula is calculated, this construction costs is calculated, drift section feature is shown in Table 1.

Drift section mark sheet table 1

1., the base price of slope mouth trench excavation gravel soil is 1125 yuan/100m³, the base price of backfill is 0.2236 ten thousand Unit/100m³。

2., inclines concrete walls supporting (inclination angle<10 ° of plank sheathings) thickness>400mm base prices be 4.7609 ten thousand yuan/ 100m³；Inclines concrete arch supporting (inclination angle<10 ° of plank sheathings) thickness>400mm base prices are 5.1640 ten thousand yuan/100m³；Tiltedly Well shaft concrete shop fixtures (inclination angle<10 ° of plank sheathings) thickness<400mm base prices are 3.9575 ten thousand yuan/100m³。

3., reinforcing bar colligation base price is 0.4427 ten thousand yuan/t.

4., slabstone mortar in ground is 2.6007 ten thousand yuan/100m³。

Cut and cover method flume part total cost：

(2), the determination of subsurface excavation method excavation length object function

During due to shallow mining method, it is not necessary to carry out large-scale earthwork excavation and filling, therefore when its construction costs is calculated, only need Consider the driving of inclines and the consuming of supporting.

1., inclines table soil undercut driving (inclination angle<10 °), excavated section>15m²Gravel soil base price is 0.5606 ten thousand Unit/100m³。

2., inclines concrete arch supporting (inclination angle<10 °) thickness<300mm base prices are 6.0844 ten thousand yuan/100m³；Tiltedly Well shaft concrete walls supporting (inclination angle<10 °) thickness<300mm base prices are 5.6414 ten thousand yuan/100m³；Inclines concrete spreads Bottom (inclination angle<10 °) thickness<400mm base prices are 3.9575 ten thousand yuan/100m³。

3., inclines gunite concrete wall supporting (inclination angle<10 °) thickness<100mm base prices be 6.5684 ten thousand yuan/ 100m³；Inclines gunite concrete arch supporting (inclination angle<10 °) thickness<100mm base prices are 7.5836 ten thousand yuan/100m³。

4., steel arch-shelf base price is 5.4969 ten thousand yuan/10t.

5., ground slabstone mortar base price is 2.6007 ten thousand yuan/100m³。

During shallow mining method, volume of excavation is V_Pick=S × l=30.70 × l.

Subsurface excavation method total cost is：

(3), contrast determines flume segment length

In summary, the cost of trench excavation and side slope gradient α₁L long with flume bottom is relevant, and during shallow mining method also with Bottom land length l is relevant, its relation curve such as Fig. 1, shown in Fig. 2.Open cut cost is with l values during flume cost equal length and adopts With the flume segment length marginal value of cut and cover tunneling.The contrast of light and dark digging cost refers to Fig. 1, Fig. 2 and table 2, table 3.In sum, manage By a length of 85.4m in flume bottom that method determines.Critical gradient takes 56.5 ° from from the aspect of cost, when trench excavation and subsurface excavation method When construction cost is equal, its flume length is about 150m, and with the reduction (44.6 °) of slope angle, flume critical length value Can reduce accordingly, when trench excavation is equal with shallow mining method cost, its flume length is about 140m.

To enter the principle in hole early, the comprehensive critical length for determining trench excavation is 80m or so to comprehensive on-site actual situations.

Critical gradient is the open cut under 56.5 ° and tunneling cost contrast table table 2

Open cut under 44.6 ° of critical gradient and tunneling cost contrast table table 3

Claims (1)

1. the critical length determining method of a kind of thick sand bed gentle slope inclined shaft cut and cover method and subsurface excavation method, the method is according to inclined shaft Inclination angle, ground line gradient, bright groove grade of side slope, shaft excavation height, Roof safety thickness and arable layer thickness gauge calculate flume and open Length value is dug, while with oblique way slope angle and excavate plagioclase as design parameter index, cut and cover method and dark has been calculated The Cost Function of digging method, it is characterised in that introduce different designs parameter index, analyzed by different designs parameter index and cost Function relative analyses, finally determine the critical length of inclined shaft open cut and tunneling：

First, trench excavation length engineering mechanics determines step

(1), trench excavation size determines

1. flume slant height H, is determined：

In formula：α-inclined shaft inclination angle；α '-ground line gradient；α₁- bright groove grade of side slope；H_Pick- shaft excavation height；h₁- top board is pacified Through thickness；h₂- arable layer thickness；

2., slot bottom width B₁：

B₁=B+0.6

In formula：B-flume shaft excavation width

3., flume width B suitable for reading₂：

B₂=B₁+2Hsinα₁

4., flume length L suitable for reading：

$L=\frac{Hsin({\mathrm{\&alpha;}}_1+\mathrm{\&alpha;})}{sin(\mathrm{\&alpha;}+{\mathrm{\&alpha;}}^{\&prime;})}$

5., the long l in flume bottom：

$l=\frac{Hsin({\mathrm{\&alpha;}}_1-{\mathrm{\&alpha;}}^{\&prime;})}{sin(\mathrm{\&alpha;}+{\mathrm{\&alpha;}}^{\&prime;})}$

6., total amount of excavation V_Dig：

7., wellbore volume V_{Pit shaft}：

S-flume section shaft excavation cross-sectional area；

8., earth volume V is backfilled_{Fill out}：

V_{Fill out}=V_Dig-V_{Pit shaft}

(2), flume length is determined in critical gradient α₀Under, flume bottom length is determined by below equation：

Flume slant height：

Flume bottom is long：

2nd, the cost of trench excavation length determines method：

(1) foundation of cut and cover method excavation length object function

By consulting《Coal builds well lane engineering Extinction efficiency》(base price in 2007) understands that slope mouth trench excavation is various Base price and the retaining portion price of soil is, it is known that the excavation and filling earth volume calculated according to above formula, calculates cut and cover method flume part Total cost, need to consider slope mouth trench excavation gravel soil, backfill expense during calculating；Reinforcing bar colligation；Ground slabstone mortar takes With；

(2) determination of subsurface excavation method excavation length object function

During due to shallow mining method, it is not necessary to carry out large-scale earthwork excavation and filling, therefore when its construction costs is calculated, only need to consider The driving of inclines and the consuming of supporting；

(3) contrast determines flume length

The cost of the trench excavation and bright groove grade of side slope α₁L long with flume bottom is relevant, and during shallow mining method also with flume bottom Long l is relevant, and with excavation length as independent variable, construction costs is dependent variable, and according to the Cost Function set up light and dark digging cost is made Contrast curve, open cut cost as adopts the bright of cut and cover tunneling with corresponding l values during flume cost equal length in figure Groove segment length marginal value.