基坑支護(hù)外文文獻(xiàn)

1、精品好資料學(xué)習(xí)推薦中文3700字Soil nail wall, also known as soil nailing technology, which is installed in situ soil with a relatively dense soil nails, and soil slope surface of sprayed concrete to build a steel mesh surface layer, through the soil nails, the surface layer and in-situ soil the role of the three

2、common slope or retaining wall side. Soil nail walls but also poses a similar gravity in situ reinforced earth retaining structures. And supporting a variety of methods have been compared, it has the construction easy, simple equipment, require little space, excavation and supporting jobs can be par

3、allel, the overall progress of the fast, low cost, as well as pollution, low noise, stable and reliable, social and economic good, and many other advantages, and therefore at home and abroad with the foundation pit slope reinforcement has been widely applied rapidly. Soil nail wall construction tech

4、nology is a top-down step by step build process, according to the following order: According to design requirements for excavation face, trimmed slope, planted sprayed concrete thickness control signs; jet first layer of concrete; erection of drilling soil nails, grouting, erection of connectors; ba

5、nding steel net, spray a second layer of concrete; set top of the hill, slope and the foot of the slope of the drainage system. Soil-nailed law-enforcement: keep as much as possible, significantly higher maximum use of pit wall side of inherent mechanical strength of soil, changing soil structure an

6、d system load as part of the bracing. Sprayed concrete under the effect of high pressure gas flow, wherein high-speed soil surface layer and the soil in the spray created between embedded solid-effect, and gradually form a completely closed with the excavation shoring systems, spray layer and mounte

7、d with a protective layer of and reinforcement of topsoil, so that to avoid exposure to wind and rain erosion, shallow collapse, local spalling, as well as the role of impermeable impermeable. Soil nailing a special control pressure grouting can be reinforced medium greatly improved physical and mec

8、hanical properties make it become a new geological body, its solid-solid in the slip plane the deep section of the soil outside the house, its external fixed terminal Spray the surface layer in conjunction with the network as a whole may be a tendency to instability in the side wall transferred to t

9、he solid-section and its vicinity and to eliminate. Reinforced Mesh sprayed layer can have a better integrity and flexibility, can effectively adjust the spray layer and the stress distribution within the soil nail. Active soil nail retaining soil and with soil together with construction of simple,

10、rapid and timely, flexible applicability, with the digging with sticks, safe and economic characteristics. Its duration is generally poorer than the traditional method to save more than 30-60d, engineering, low cost and 10% -30%, supporting the maximum vertical pit depth has now reached 21.5m, built

11、 mud (local miscellaneous fill) pit depth of 10m. This method not only effectively be used for general geotechnical deep excavation shoring, often also used a number of other ancillary support measures, can effectively be used for supporting streaming sand, silt, complex filling, saturated soil, sof

12、t soil, etc. adverse geological conditions of the deep excavation. In addition, it is also rapid, reliable and economical method of using the traditional method or improved facilities to be made or have been carried out rescue excavation instability reinforcement. Of soil nailing and reinforced soil

13、 and anchor it seems such as retaining structures, however, the structure of soil nailing and reinforced earth construction, etc. There are many different points, and anchor. First of all, soil nailing and reinforced soil slope or retaining wall is not the same, mainly reflected in: the construction

14、 in different ways. Soil-nailed construction of the distribution of expansion from top to bottom, side excavation while retaining full use of undisturbed soil strength. Reinforced earth structure from bottom to top filling layered construction, filling choice, density and intensity can be controlled

15、; reinforced pull the biggest changes in body pattern is different. In the reinforced earth structure, the general body at the bottom of the tendon force maximum. In the structure of soil nailing, the general range of the central part of the largest force of soil nail, the upper and bottom of the so

16、il nail force small; different deformation properties. Soil Nailing the maximum displacement occurred in the supporting slope at the top or near the top, reinforced earth structure, the maximum displacement at the bottom. Secondly, soil nailing and bolting or retaining wall is not the same, mainly d

17、ue to: the various parts of the force and the same role. Bolting or retaining wall of the anchor generally anchorage section and free above, the use of sliding surface to provide resistance outside the anchorage section, set the anchor generally prestressed, the free section under uniform tension ef

18、fect, through the anchor seat passed to the slope of the retaining structures, earth retaining structures greater stiffness, mainly through the provision of resistance by the moment, is one of the main force components. Soil nailing settings generally do not impose pre-tension, but occurs in the soi

19、l after a small deformation of the passive force, the size of the force along the uneven distribution of soil nail extension, the middle on both sides of the small, the role of the force at the surface layer than the small, sprayed concrete surface layer is not a major force components, its role is

20、to stabilize the surface of the partial excavation of soil to prevent caving and erosion; setting different densities. In the bolt support in the unit area on the retaining bolt set the number of generally less, for each root anchor construction accuracy and requirements are very stringent. In the s

21、oil-nailing, the surface of soil nail retaining a little bit more dense arrangement of individual soil nail construction relatively low accuracy and quality requirements; design of different lengths. In the bolt support, the design requirements must meet the requirements of each root anchor of resis

22、tance, so bolt anchorage section require in-depth into the stable layer, the design of a longer length. In soil nailing, the more dense arrangement of soil nail, the large number of interaction with the surrounding soil, to maintain self-reinforced zone of soil stability, and resistance to outside t

23、he region reinforced the role of soil pressure, design shorter length. Of course, there are many types of bolts, there are not pre-stressed, the length than the average soil-nail even shorter, but this bolt is mainly used for the tunnel or underground works of the spray-anchor on the length than the

24、 average soil-nail is also is shorter, often only 2-4m. （1）Construction of Soil Nail Soil nailing is a soil-nail as a major component of the slope of the force supporting technology, which consists of dense soil nail group, has been reinforced in situ soil, sprayed concrete surface layer and the nec

25、essary water system components. （2）Structural Materials Steel: steel types, models and sizes should be consistent with design requirements, should adopt the H-or H-class steel workers, reinforced after the purchase should be properly safeguarded to prevent corrosion, production should be transferred

26、 straight, rust, oil removal, should be carried out physical and mechanical properties or chemical composition analysis of test welding of steel, should be weldability and welding quality of the test for detection of welding material strength should be greater than the overall strength; Cement: ordi

27、nary portland cement used, label P032.5, if necessary, sulfuric acid resistant cement, alumina cement should not be used. Cement should comply with the provisions of the existing cement standard requirements, there must be a single factory test reports, quality inspection orders, factory card docume

28、nts, in accordance with its varieties, label, test numbers etc., and inspection and acceptance sampling inspection, by the examination results are reasonableUse. Bags of cement should be properly kept in storage and transportation, rain, moisture, stacked in a certain height from the ground heap she

29、lves, is strictly prohibited and damage throwing throwing bags, prohibited the use of damp or different varieties of mixed cement label. Aggregate: stone and sand material (seeds film, medium-fine sand) should check report cards, the stone test methods and quality standards by JGJ53-92, sand materia

30、l testing methods and quality standards by JGJ52-92. Particle size of less than 2mm in the sand, sand, clay content by weight not more than 3%, the particle size of less than 12mm gravel or melon tablets, clay content by weight not more than 3%. Mixing of water: the water without affecting the norma

31、l condensation of cement hardening of harmful impurities, may not contain fat, sugar and free acid, etc.; water, PH value is less than four of acidic water and sulfur ion of more than 1% of the water weight of water were shall not be used; the use of tap water or clean water for mixing natural water

32、 could be dispensed with for testing. Quick-setting agent: quick-setting agent is used in J85, 711, or Red Star 1, should be specifically responsible for control, add the weight of 3% of the weight of cement, the machine automatically added by the jet. Electrodes: The THJ422. Concrete mix: In additi

33、on to spraying the concrete mix design standards to be attained strength, we must also meet the technical requirements of construction, with the ratio of 1:0.4:2:2 (cement: water: sand: melon pieces), melon seeds piece maximum diameter of not more than 12mm. Grouting mixture ratio: one-grouting with

34、 cement mortar 1:1, the second grouting using water-cement ratio of 0.5 water slurry, cement mortar and cement slurry must be stirred evenly pure, a mixing of the slurry must be initial setting before ( generally 2h) run out. Early strength and water-reducing agent: According to the nature of projec

35、ts, using different types of early strength agent, commonly used red star on the 4th, 3F, NC, NNOF, NS2-1 and so on. （3）Net production of soil nailing and reinforced Size allowable deviation of soil nail making: the length of ?100mm, curved reposted elsewhere in the paper for free download （4）Draina

36、ge System Soil Nailing appropriate to remove ground water under the conditions of construction, the drainage should take appropriate measures, including surface drainage, internal drainage, as well as supporting the drainage pit in order to avoid saturation of the soil and reduce the role of the hyd

37、rostatic layer on the surface pressure. Excavation around the bracing should be added within the surface finishing, and building drains and cement mortar or concrete surface to the underground water surface infiltration of precipitation. Pit top of the hill near the 2-4m wide and the ground should b

38、e properly boosted, and the inside of high external low, easy to run-off away from the slope. In supporting the back surface layer should be inserted in a length of 400-600mm, diameter of not less than the standard 40mm drain out its external side supporting surface layer spacing for 1.5-2m, in orde

39、r to spray the plot after the surface layer of concrete water discharge. To rule out the accumulated water seepage inside the pit and rain should be set 300mm * 300mm Bottom drains, leads to the 600mm * 600mm * 600mm sump. Drains, leave the side wall 0.5-1m, drains and sump is appropriate to brick a

40、nd mortar Plastering used to prevent leakage, pit water should be out in time. Mechanism of composite soil nail force.In the soil nailing system, the soil nail is an important force components, the role of soil nail will act on the surface layer or soil-cement pile on the water, soil pressure, soil

41、nail and soil through the mill passed to the stability of the resistance Formation to go, similar to the soil anchor; through the dense and the soil nails will be a short retaining body deformation Houtu bound together to form from the soil, grouting and soil nailing body a composite soil, composite

42、 soil similar to the on the force of gravity dam. This role is similar to reinforced earth retaining pit; no matter what form of construction of soil nail (hole-drilling method, and entering the law and the roof into the law), soil nailing channels are grouting holes, which not only formed a soil gr

43、outing nail retaining wall and the formation of friction between the belt, at the same time in order to split, penetration and compaction grouting in the form of reinforced retaining Houtu body, such a role similar to the mechanism of compaction grouting. The process of soil nail force Measurements

44、showed that the process of soil nail force can be divided into three stages: Phase I: soil nail installed an early stage, but the completion of grouting grouting of the bonding between the body and the soil has not been formed, when the soil nail largely unaffected by power. Phase II: grouting body

45、of the soil nail bonding in the formation, with the excavation depth increases, soil nailing has the effect of tension, and tension concentrated in the surface layer bonded with the site, then internal force distribution is similar to non - Free-form deformation of the soil anchor segment near the s

46、urface layer at the biggest rally, the subsequent decrease gradually. The third phase: excavation of sufficient depth, soil nailing most of the slip at the range. At this time the performance of soil nailing for the middle of internal force (near the slip surface) the largest and the smallest at bot

47、h ends. Force distribution is similar to reinforced earth retaining wall in the stretch.土釘墻又稱為土釘支護(hù)技術(shù)，它是在原位土中敷設(shè)較為密集的土釘，并在土邊坡表面構(gòu)筑鋼絲網(wǎng)噴射混凝土面層，通過(guò)土釘、面層和原位土體三者的共同作用而支護(hù)邊坡或邊壁。土釘墻體同時(shí)也構(gòu)成了一個(gè)就地加固的類似重力式擋土結(jié)構(gòu)。與已有的各種支護(hù)方法相比，它具有施工容易、設(shè)備簡(jiǎn)單、需要場(chǎng)地小，開挖與支護(hù)作業(yè)可以并行、總體進(jìn)度快、成本低，以及無(wú)污染、噪聲小、穩(wěn)定可靠、社會(huì)效益與經(jīng)濟(jì)效益好等許多優(yōu)點(diǎn)，因而在國(guó)內(nèi)外的邊坡加固與基坑支護(hù)中得到了廣泛

48、迅速的應(yīng)用。土釘墻的施工技術(shù)是一種由上而下分步修建的過(guò)程，可按下列順序進(jìn)行:按設(shè)計(jì)要求開挖工作面，修整邊坡，埋設(shè)噴射混凝土厚度控制標(biāo)志;噴射第一層混凝土;鉆孔安設(shè)土釘、注漿、安設(shè)連接件;綁扎鋼筋網(wǎng)，噴射第二層混凝土;設(shè)置坡頂、坡面和坡腳的排水系統(tǒng)。土釘支護(hù)法:以盡可能保持、顯著提高、最大限度地利用基坑邊壁土體固有力學(xué)強(qiáng)度，變土體荷載為支護(hù)結(jié)構(gòu)體系一部分。噴射混凝土在高壓氣流的作用下高速噴向土層表面，在噴層與土層間產(chǎn)生“嵌固效應(yīng)”，并隨開挖逐步形成全封閉支護(hù)系統(tǒng)，噴層與嵌固層同具有保護(hù)和加固表層土，使之避免風(fēng)化和雨水沖刷、淺層坍塌、局部剝落，以及隔水防滲作用。土釘?shù)奶厥饪貕鹤{可使被加固介質(zhì)物理

49、力學(xué)性能大為改善并使之成為一種新地質(zhì)體，其內(nèi)固段深固于滑移面之外的土體內(nèi)部，其外固端同噴網(wǎng)面層聯(lián)為一體，可把邊壁不穩(wěn)定的傾向轉(zhuǎn)移到內(nèi)固段及其附近并消除。鋼筋網(wǎng)可使噴層具有更好的整體性和柔性，能有效地調(diào)整噴層與土釘內(nèi)應(yīng)力分布。土釘主動(dòng)支護(hù)土體并與土體共同作用，具有施工簡(jiǎn)便、快速及時(shí)，機(jī)動(dòng)靈活、適用性強(qiáng)、隨挖隨支、安全經(jīng)濟(jì)等特點(diǎn)。其工期一般比傳統(tǒng)法節(jié)省30-60d以上，工程造價(jià)低10%-30%，支護(hù)最大垂直坑深目前已達(dá)到21.5m，建成淤泥(局部雜填土)基坑深達(dá)10m。該方法不僅能有效地用于一般巖土深基坑工程支護(hù)，而且通常還采用一些其他輔助支護(hù)措施，能有效地用于支護(hù)流砂、淤泥、復(fù)雜填土、飽和土、軟

50、土等不良地質(zhì)條件下的深基坑。此外，它還能快速、可靠、經(jīng)濟(jì)地對(duì)采用傳統(tǒng)法或改良法施作的將要或已經(jīng)失穩(wěn)的基坑進(jìn)行搶險(xiǎn)加固處理。土釘支護(hù)似乎與加筋土和錨桿等擋土結(jié)構(gòu)一樣，然而土釘支護(hù)在結(jié)構(gòu)施工等方面與加筋土和錨桿有許多不同點(diǎn)。首先，土釘支護(hù)與加筋土邊坡或擋墻不相同，主要表現(xiàn)在:施工方法不同。土釘支擴(kuò)從上到下分布進(jìn)行修建，邊開挖邊支護(hù)，充分利用原狀土的強(qiáng)度。加筋土結(jié)構(gòu)由下到上分層填土構(gòu)筑，填料可以選擇，密實(shí)度和強(qiáng)度可以控制;加筋體最大拉力的變化規(guī)律不同。在加筋土結(jié)構(gòu)中，一般處于下部的筋體受力最大。在土釘支護(hù)結(jié)構(gòu)中，一般介于中部的土釘受力最大，上部和底部的土釘受力較小;變形性能不同。土釘支護(hù)最大位移發(fā)生

51、在支護(hù)邊坡頂部或接近頂部，加筋土結(jié)構(gòu)的最大位移在底部。其次，土釘支護(hù)與錨桿支護(hù)或擋墻也不相同，主要在于:各部分的受力和作用不同。錨桿支護(hù)或擋墻中的錨桿一般都有錨固段和自由段，利用滑動(dòng)面以外的錨固段提供抗力，設(shè)置錨桿一般要施加預(yù)應(yīng)力，自由段受到均勻的拉力作用，通過(guò)錨座傳遞到坡面的擋土構(gòu)件上，擋土構(gòu)件的剛度較大，主要通過(guò)受彎矩提供抗力，是主要的受力部件之一。土釘設(shè)置后一般不施加預(yù)拉力，只是在土體發(fā)生微小變形后才被動(dòng)受力，受力的大小沿土釘延長(zhǎng)的分布不均勻，中間大兩邊小，所作用在面層上的力較小，噴射混凝土面層不是主要受力部件，其作用是穩(wěn)定開挖面上的局部土體，防止崩落和受到侵蝕;設(shè)置密度不同。在錨桿支護(hù)

52、中，單位支護(hù)面積上設(shè)置的錨桿數(shù)量通常較少，對(duì)每根錨桿的施工精度和要求都十分嚴(yán)格。在土釘支護(hù)中，支護(hù)面上土釘排列得較密，對(duì)單個(gè)土釘?shù)氖┕ぞ群唾|(zhì)量要求相對(duì)較低;設(shè)計(jì)長(zhǎng)度不同。在錨桿支護(hù)中，設(shè)計(jì)要求每根錨桿都要達(dá)到要求的抗力，所以錨桿的錨固段需要深入到穩(wěn)定的土層中，設(shè)計(jì)長(zhǎng)度較長(zhǎng)。在土釘支護(hù)中，土釘排列較密，數(shù)量眾多，與周圍土層共同作用，能夠保持加固區(qū)土體的自身的穩(wěn)定，并抵抗加固區(qū)以外的土壓力的作用，設(shè)計(jì)長(zhǎng)度較短。當(dāng)然，錨桿有許多種類，也有不加預(yù)應(yīng)力、長(zhǎng)度比一般的土釘還要短，但這種錨桿主要用于隧道或地下工程的噴錨支護(hù)上，長(zhǎng)度比一般的土釘還要短，常用只有2-4m。（1）土釘墻結(jié)構(gòu)組成土釘支護(hù)是以土釘作為主要受力構(gòu)件的邊坡支護(hù)技術(shù)，它由密集的土釘群、被加固的原位土體、噴射混凝土面層和必要的防水系統(tǒng)組成。（2）土釘墻結(jié)構(gòu)材料鋼材:鋼筋的種類、型號(hào)及尺寸規(guī)格應(yīng)符合設(shè)計(jì)要求，宜采用H