1 General Provisions
1.0.1 This code is formulated in order to unify the engineering design standards of coal mine shaft, shaft equipment and relevant chamber as well as to improve design quality.
1.0.2 This code is applicable to the engineering design of coal mine shaft and relevant chamber.
1.0.3 In design of coal mine shaft and chamber, it shall embody the principle of advanced technology, safety and reliability as well as economy and rationality, positively promote application of proved mature scientific research achievement as well as adopt new technique, new process and new material according to local conditions to improve comprehensive efficiency of design.
1.0.4 In engineering design of coal mine shaft and chamber, there must be shaft examination and drilling information meeting the design requirements and it shall determine the optimum design through making technical and economic comparison between multiple schemes according to relevant data.
1.0.5 As for material used for coal mine shaft and chamber engineering, its property, specification and quality shall meet the relevant national standards.
1.0.6 The engineering design of coal mine shaft and chamber shall not only meet the requirements stipulated in this standard (code), but also comply with those in the current relevant ones of the nation.
2 Terms and Main Symbols
2.1 Terms
2.1.1 Guide
The guide is a kind of guiding facility in shaft to lift container for operation. The common flexible guide includes steel-rope guide while rigid guide covers rail guide, formed-steel assemble guide, square cold-formed steel guide, cold-drawn square-pipe formed steel guide, GRP composite guide and wood guide.
2.1.2 Alluvium
It is covered on the Quaternary system above bedrock and the tertiary stratum of unformed rock.
2.1.3 Single-layer lining
The lining refers to a layer of structures composited by reinforced concrete and concrete or by steel plate and reinforced concrete (or concrete). It is poured onsite or prefabricated on ground after sublevel drive of shaft. Its thickness and strength shall be able to bear the action of temporary load and permanent ground pressure
2.1.4 Double-layer lining
It is composed of outer-layer lining and inner-layer lining. The outer-layer lining refers to short-section excavation and lining of shaft to a certain depth from up to down while the inner-layer lining is poured from down to up. The outer-layer lining shall be able to bear freezing pressure; the inner-layer lining shall be able to bear hydrostatic pressure; the thickness and strength of inner-layer and outer-layer lining shall be able to bear permanent ground pressure and add load of vertical.
2.1.5 Add load of vertical
The vertical downward force on lining due to settlement caused by stratum dewatering or other factors.
2.1.6 Characteristic value of load
The value of load with no consideration of structural safety factor.
2.1.7 Effective value of load
The value of load of standard load multiplied by safety coefficient.
2.1.8 Load-carrying
The capacity for lining to bear load (or internal force).
2.1.9 Thin shell tube
A kind of shell tube, the ratio of whose lining thickness and internal radius is less than the specified value. In shaft, when the ratio of lining thickness t and the center radius r0 of shaft lining is less than 10 , it is called thin shell tube.
2.1.10 Thick shell tube
A kind of shell tube, the ratio of whose lining thickness and internal radius is greater than the specified value. In shaft, when the ratio of lining thickness t and the center radius of shaft lining is greater than or equal to 10 , it is called thick shell tube.
2.2 Main symbols
2.2.1 shaft sinking and shaft support by common method and freezing method
A0—Sectional area of calculated section lining;
An—Coefficient of horizontal load on rock (soil) strata;
As—Area of reinforcement location section on lining per meter
b—Calculated width of lining section;
D—External diameter of shaft;
d—Internal diameter of shaft;
Ec—Elastic modulus of concrete;
—Elastic modulus of reinforcement;
—External surface area of lining above calculated section;
—Design value of concrete axes compression strength;
—Standard value of concrete cube compressive strength;
—Design value of lining material strength;
—Design value of concrete tensile strength;
—Design value of compressive and tensile strength of ordinary reinforcement;
H—Design depth of lining at calculation section;
I—Inertia moment of shaft cross-section;
L0—Calculated length of lining ring at calculation section;
M0—Horizontal bending moment of build-in shaft tower;
N—Calculated value of axial force on lining ring section per unit height;
N0—Horizontal axial force of build-in shaft tower;
P—Calculated value of design load on lining at calculation section;
Pk—Standard value of uniform load on structure;
PA,k, PB,k—Standard value of minimum and maximum load on lining;
Pf,k—Standard value of add load of vertical for unit external surface area of lining above calculated section;
, —Standard value of uniform load on lining from nth layer of rock head or base plate;
Q0—Horizontal force of build-in shaft tower;
Q1, k—Standard value for weight of shaft tower directly supported by shaft;
Q2, k—Standard value of shaft equipment weight above calculated section;
Qf, k—The sum of standard value of add load of vertical on lining above calculated section;
QZ, k—Standard value of vertical load on lining;
QZ, k—Standard value of deadweight of lining above calculated section;
r0—Center radius of lining at calculation section;
rn—Internal radius of lining at calculation section;
rw—External radius of lining at calculation section;
t—Thickness of lining;
—Safety coefficient of structure;
—Stability coefficient of compression members of reinforced concrete axes;
—Stability coefficient of plain concrete member;
—Friction angle inside soil strata;
—Coefficient of non-uniform load on alluvial formation;
—Non-uniformity coefficient of horizontal load on rock strata;
—Poisson's ratio of concrete;
—gravity density of concrete (or reinforced concrete);
—Reinforcement ratio of lining ring section;
—Minimum reinforcement ratio of lining ring section;
—Tangential stress of lining ring section;
—Calculated value for self weight stress of calculated section lining;
—Calculated value for longitudinal stress of calculated section lining;
—Calculated value for radial stress of calculated section lining.
2.2.2 Shaft sinking and shaft support by drilling method
Asy—Cross-sectional area of lining vertical reinforcement;
Ay, —Sectional area of tensile and compressive reinforcement;
Ds—Design diameter of shaft net section;
Dy—Effective diameter of shaft net section;
hz—Section height of lining;
NZk—Standard value of vertical load on lining in hoisting;
n—Ratio of elastic modulus between reinforcement and concrete;
Pw.k—Standard value of slurry pressure;
Pnh—Standard value of counterweight water pressure;
Pg—Calculated value of pressure on lining bottom;
Pw—Calculated value of slurry pressure;
Pn—Calculated value of counterweight water pressure;
VQ, VT—Volume of shell and drum;
Vn—Volume of slurry displaced by shell and drum on lining bottom;
—Safety coefficient of crack resistance;
—Constant of shell;
—Inclination rate of well completion in design;
—Gravity density of slurry;
—Gravity density of counterweight water;
2.2.3 Shaft sinking and shaft support by open caisson method
—Design internal diameter of open caisson;
d1—Effective internal diameter of open caisson;
D—External diameter of shaft open caisson;
D1—External diameter of edge foot;
D2—Internal diameter of casing shaft;
D3—External diameter of casing shaft;
E—Thickness of lining of casing shaft;
F—Unit friction resistance between lining and soil direct contact surface;
F′—Unit friction resistance between lining and slurry;
C—Deadweight of open caisson lining;
G′—Total weight of open caisson (deducting flotage);
G1—Deadweight of edge foot of open caisson lining (not deducting flotage);
G2—Weight of open caisson shaft (not deducting flotage);
G3—Weight of slurry drum behind open caisson lining (not deducting flotage);
h—Thickness of open caisson lining;
H—Effective depth of open caisson;
H1—Total depth of casing shaft;
H2—Height from below edge foot tip of casing shaft to edge foot step of open caisson;
H3—Height of edge foot;
L1—Clearance between open caisson and casing shaft;
N—Head resistance of open caisson;
R1—Ultimate compression strength of soil;
S—External surface area of open caisson lining;
T—Total resistance of open caisson sinkage;
T1—Side resistance between edge foot outside and soil strata;
T2—Friction resistance between thixotropic slurry and lining outside;
W—Calculated weight ratio of lining;
—Depth of edge foot in soil strata;
—Included angle of edge foot tip;
—Allowable inclination rate of open caisson;
—Inclination rate of casing shaft;
2.2.4 Shaft sinking and shaft support by concrete curtain method
B0—Thickness of casing wall;
B—Effective thickness of concrete curtain;
D—Diameter of drilling hole;
H—Designed depth of concrete curtain;
R—Net radius of curtain effective thickness;
R0—Net radius of shaft;
R1—Radius of curtain central line;
—Maximum allowable inclination rate of pore-forming.
