AM3 main board mining

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2.

1. Type and structure of anchor rod (cable)

anchor rod is a component that transmits tensile force to stable rock and soil layer. When steel strand or high-strength steel wire bundle is used as rod material, it can also be called anchor cable. The anchor anchored in the soil is called soil anchor; The rock bolt anchored in the rock is called rock bolt. The prestressed anchor is called prestressed anchor; The anchor without prestress is called non prestressed anchor. In addition, there are several main methods of anchor classification

According to the pull rod material, it can be divided into wood bolt and metal bolt

2) according to the type of anchor head, it can be divided into mechanical type (wedge type, internal expansion type), cemented type (grouting type, resin type)

According to the construction method of controlling deformation, it can be divided into ordinary anchor and prestressed anchor

According to the service life, it can be divided into temporary anchor and permanent anchor

in the anchoring construction of slope collapse or dangerous rock mass, the friction grouting anchor is used most. Grouting anchor is a kind of columnar anchor body which uses cement mortar to anchor a group of steel tie rods in the borehole extending into the stratum and bears tensile force. The drilling direction of grouted bolt generally inclines downward 10 °～ forty-five °， During construction, the drilling depth must exceed the buried depth of sliding surface, and reach enough effective anchorage length in stable rock and soil layer. It is commonly said that the maximum tensile force of the effective anchorage section of the anchor end anchored into the rock and soil layer is the ultimate pull-out force of the anchorage section. The main factor affecting the pullout resistance of grouted bolt is the binding capacity of mortar. Therefore, in order to ensure the reliability of grouting anchor, it is necessary to investigate the basic characteristics of slope rock and soil, and design the parameters of anchor according to the properties of rock and soil. The composition of grouting bolt is shown in Fig. 2-14

The anchor is composed of three parts: anchor solid, pull rod and anchor head. After the structure or other forces are transmitted to the bolt head, the pull force from the bolt head is transmitted to the anchor solid by the pull rod, and then the anchor solid is transmitted to the rock and soil layer through the friction resistance

The stress analysis of

anchor is shown in Fig. 2-15. The main forces on the bolt are: 1) tensile force (T); ② Binding force of mortar μ ③ Formation friction resistance τ Where T < sub > I < / sub > = P < sub > I < / sub > A (P < sub > I < / sub > is the stress on the unit section of the reinforcement; A is the cross-sectional area of the reinforcement

Fig. 2-14 composition diagram of grouting anchor rod

Fig. 2-15 stress state diagram of grouting anchor rod

the conditions that the pull-out resistance of anchor rod should meet are as follows: 1) the binding force of mortar in anchorage section for steel tie rod should be able to bear ultimate tensile force; ② The friction force of rock and soil layer to mortar in anchorage section should be able to bear ultimate tensile force; ③ The anchorage rock and soil can still maintain the overall stability under the worst conditions

(1) the bond strength of mortar to steel tie rod is related to not only the effective anchorage length, but also the diameter of anchor rod and the average bond stress of mortar to steel bar. The following formula should be satisfied:

geological disaster prevention and control technology

where T < sub > U < / sub > is the ultimate pull-out force of anchor rod or the binding force of mortar to steel tie rod (KN); D is the diameter of steel tie rod (m); L < sub > e < / sub > is the effective anchorage length (m); μ Is the average bond stress of mortar to reinforcement (KN / M < sup > 2 < / sup >)

The binding force per unit area of

reinforcement is calculated by the following formula:

geological disaster prevention technology

where T < sub > I < / sub >, T < sub > I + 1 < / sub > are the tensile stress (KN) at the I and I + 1 sections respectively; μ I is the average bond stress (KN / M < sup > 2 < / sup >) of the mortar in the I anchorage section to the reinforcement; L < sub > I < / sub > is the length of the i-th anchorage section; The meanings of other symbols are the same as before

e to the complexity of anchoring force, in practical work, it is generally increased by 10% ~ 20% on the basis of the calculated value. If the ultimate tensile stress of anchor bar is n < sub > s < / sub >, the minimum anchorage length of anchor bar can be calculated according to the following formula:

geological disaster prevention technology

where l < sub > Emin < / sub > is the minimum anchorage length; The meanings of other symbols are the same as before

(2) the friction of rock and soil layer on mortar in anchorage section

the ultimate uplift capacity of anchor depends on the maximum friction of rock and soil layer on mortar in anchorage section. The calculation formula is

geological disaster prevention and control technology

where T < sub > U < / sub > is the ultimate uplift force (KN) of cylindrical anchor body; D is the diameter of the anchor hole (m); L < sub > e < / sub > is the effective anchorage length (m); τ Is the shear strength around the anchorage section (kPa)

The shear strength of the hole wall in the anchorage section is the failure strength of the hole wall. There are three reasons for the failure: 1) the shear failure of the rock around the mortar interface; ② Shear failure occurs along the interface between mortar and hole wall; ③ The shear failure of mortar in the interface

for soil anchor, the strength of soil layer is generally lower than that of concrete mortar, so the calculation formula of soil shear strength is

geological disaster prevention technology

or

geological disaster prevention technology

, where: γ It is the weight of soil layer in Anchorage Zone (KN / M < sup > 3 < / sup >); C is the cohesion of soil layer in Anchorage Zone (kPa)&# 59272; Is the internal friction angle of soil °σ Is the normal stress around the hole wall (kPa); H is the overburden thickness above the anchorage section (m); K < sub > 0 < / sub > is the earth pressure coefficient of the hole wall of the anchorage section, generally taken as 1; The meanings of other symbols are the same as before

3. Design of anchor rod (cable)

(1) material type of anchor rod (cable)

the common material types of anchor rod (cable) are ordinary steel bar (HRB335, HRB400 (grade II, grade III)), finish rolled threaded steel bar, high strength steel wire or steel strand. The commonly used anchor material in our country is the finish rolled coarse rebar with a diameter of Φ 22～32mm In recent years, 45simnv high strength steel with diameter of Φ In addition, steel strand and wire bundle are also used. See table 2-12 for the selection of anchor rods of various material types

Table 2-12 see Appendix E of technical code for building slope engineering (GB 50330-2002) for mechanical properties of anchor rod (cable) type selection

steel strand or finish rolled rebar. When the slope deformation is strictly controlled or the stability of the slope is very poor ring the construction period, the prestressed anchor should be used

(2) calculation of bolt (cable)

the design value of axial tension of bolt (cable) is calculated according to the following formula:

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where n < sub > a < / sub > is the design value of axial tension of bolt (cable) (KN); N < sub > AK < / sub > is the standard value of axial tension of anchor (cable) (KN); γ< sub> α is the partial load factor, taking 1.3. When the variable load is large, it shall be determined according to the load code

the standard value of axial tension of bolt (cable) is calculated according to the following formula:

geological disaster prevention and control technology

where n < sub > AK < / sub > is the standard value of axial tension of bolt (cable) (KN); H < sub > TK < / sub > is the standard value of horizontal tension (KN) of anchor (cable); α Is the inclination angle of anchor rod (cable) °

the cross-sectional area of anchor bar should meet the requirements of the following formula:

geological disaster prevention technology

Where a < sub > s < / sub > is the cross-sectional area of anchor bar or prestressed steel strand (m < sup > 2 < / sup >); ξ 2 is the tensile working condition coefficient of anchor bar, 0.69 for permanent anchor and 0.92 for temporary anchor; γ< Sub > 0 < / sub > is the importance coefficient of slope engineering; F < sub > y < / sub > is the design value of tensile strength of anchor bar or prestressed steel strand (kPa); The meanings of other symbols are the same as before

the length of the anchor section should meet the requirements of the minimum anchor length specified in the structural design, in addition to the requirements of the binding force of the stratum to the mortar and the binding force of the mortar to the reinforcement

the anchoring length between the bolt and the stratum should meet the requirements of the following formula:

geological disaster prevention technology

where l < sub > a < / sub > is the length of the anchoring section (m); D is the diameter of anchor (m); F < sub > RB < / sub > is the characteristic value (kPa) of bond strength between stratum and anchor, which should be determined by test or local experience. If there is no test data, it can be selected according to table 2-13 and table 2-14; ξ< Sub > 1 < / sub > is the working condition coefficient of the bonding between the stratum and the anchor solid, 1.00 for permanent anchor and 1.33 for temporary anchor; The meanings of other symbols are the same as before

Table 2-13 characteristic value of bond strength between rock and anchor solid; The data in the table is only applicable to the preliminary design, and should pass the test ring construction; When the rock mass discontinuity is developed, the middle and lower limits of the table are taken; The rock types in the table are classified according to natural uniaxial compressive strength (f < sub > R < / sub >): F < sub > R < / sub > & lt; 5MPa is very soft rock, 5MPa ≤ f < sub > R < / sub > & lt; 15MPa is soft rock, 15MPa ≤ f < sub > R < / sub > & lt; 30MPa is soft rock, 30MPa ≤ f < sub > R < / sub > & lt; 60 MPa is hard rock, f < sub > R < / sub > ≥ 60 MPa is hard rock

Table 2-14 characteristic value of bond strength between soil and anchor body; The data in the table is only applicable to the preliminary design, and should pass the test inspection ring construction

the anchoring length between anchor bar and anchoring mortar should meet the following requirements:

geological disaster prevention technology

where l < sub > a < / sub > is the length of anchoring section (m); D is the diameter of anchor bar (m); N is the number of anchor bars; F < sub > b < / sub > is the design value of bond strength between anchor bar and anchorage mortar (kPa), which should be determined by test or local experience. If there is no test data, it can be selected according to table 2-15; ξ 3 is the working condition coefficient of bond strength between anchor bar and anchoring mortar, 0.60 for permanent anchor and 0.72 for temporary anchor; The meanings of other symbols are the same as before

Table 2-15 design value of bond strength between anchor bar and anchorage mortar (unit: MPa)

note: when two bars are spot welded into bundles, the bond strength shall be multiplied by 0.85 rection factor; When three bars are spot welded into bundles, the bond strength should be multiplied by 0.7 rection factor; The number of bundled steel bars shall not exceed 3, and the total cross-sectional area of steel bars shall not exceed 20% of the anchor hole area. When the reinforcement and grouting material of the anchorage section are specially designed and the anchorage effect is verified by the test, the amount of the anchorage reinforcement can be appropriately increased

The tensile deformation of the unbonded non prestressed rock bolt in the free section is basically the elastic deformation of the steel bar in the free section, and its horizontal deformation value is calculated by the following formula:

geological disaster prevention technology

where: δ< Sub > b < / sub > is the horizontal deformation value of bolt (m); H < sub > TK < / sub > is the standard value of horizontal tension (KN) on the bolt; K < sub > b < / sub > is the horizontal stiffness coefficient of bolt (KN / M)

The horizontal stiffness coefficient of bolt should be determined by bolt test. When there is no test data, the horizontal stiffness coefficient of the unbonded non prestressed rock bolt in the free section can be calculated by the following formula:

geological disaster prevention technology

Where a is the cross-sectional area of the bolt (m < sup > 2 < / sup >); L < sub > F < / sub > is the length of the free section of the bolt (m); E < sub > s < / sub > is the elastic molus of the rod (kPa); The meanings of other symbols are the same as before

The tensile deformation of prestressed rock bolt and fully bonded rock bolt can be neglected

The total length of the bolt is the sum of the length of the anchoring section, the free section and the outer anchoring section. The length of the free section of the anchor is calculated according to the length from the outer anchor head to the potential sliding surface

3.

What's the difference between soil nail and anchor rod? How to distinguish them? To solve this problem, first of all, we need to know what is called soil nailing and anchor rod. According to the definition given in the book "technical code for building slope engineering", the so-called anchor rod refers to the component that transmits the tensile force to the stable rock and soil layer. When steel strand or high strength steel wire bundle is used as rod material, it can also be called anchor cable

Finally, their working mechanism is different. As the fulcrum of retaining components such as pile and wall, the anchor transfers the lateral earth pressure acting on the pile and wall to the deep soil through the free section and anchorage section. Except for the anchorage section, the bolt receives the same tensile force in the length of the free section; However, the tension of soil nailing varies along its whole length, which is generally large in the middle and small at both ends. The shotcrete surface in soil nailing support is not the main retaining part. Under the self weight of soil, its main function is to stabilize the local soil on the excavation surface and prevent its collapse and erosion. Soil nailing is a kind of retaining structure, which is similar to gravity retaining wall. In addition, the number of anchors is usually limited, while the soil nails are densely arranged, so the construction accuracy and quality requirements are not as strict as anchors. Of course, there are also some special cases of grouting and soil bonding along the whole length without prestressing in the anchor, which will be transferred to the soil nailing under the specific arrangement< br />

4. When you say anchor bolt, do you mean expansion bolt or planting steel bar and gluing steel bar. The expansion bolt should be determined by pull-out test on site. Planting glue should be in accordance with the instructions.

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8.

1. ASUS m4a77t: reference price: 649

CPU type: phenomenii / Athlon II / sempron10

integrated chip: sound card / network card

display chip: no

motherboard: ATX board

USB interface: 12 × USB2.0 interface (6 built-in + 6 backplane)

SATA interface: 6 × Sataii interface

PCI slot: 3 × PCI slot

mainboard bus: ht3.0 maximum support 5.2gt/s

network card chip: board realtekrtl8112l gigabit network card

extended data:

AM3, full name is socket AM3, is a CPU interface specification. AM3 CPU can be physically compatible with the old socket-am2 + socket or even the earlier socket-am2 socket. AM3 processor can also work directly on socket-am2 + motherboard

at present, AM3 processor can only support a set of memory mole channels to operate in the bandwidth of ddr3-1333, and it can only provide the bandwidth of ddr3-1066 when it is equipped with four memory moles

motherboard purchase principle:

the motherboard of a computer has a great impact on the performance of the computer. Some people once compared the main board to the foundation of a building, whose quality determines whether the building is strong and rable; Some people vividly compare the main board to viact, whose quality is related to the smooth force and velocity of traffic

1. Stable operation and good compatibility

2. Perfect function and strong expansibility

It is easy to use and can adjust as many parameters as possible in BIOS

4. The manufacturer has a website with timely update and rich content, which is convenient for maintenance

5, the price is relatively cheap, that is, high cost performance

9. It depends on the motherboard model. The newer model 780g 790g can directly recognize AM3 CPU without brushing. If you don't recognize it, please go to the official website of the motherboard to download it. Please refer to the instructions for specific steps.