【正文】 In the late 39。t economy. (4) for the new Ip 20 of the index of soil, must pay attention to carefully evaluate the creep characteristics rear can use. (5) for water cut rich silty sand layer, sandy pebble soil nailing layer is no good method. (6) does not apply to no temporary stability ability of silt from the soil and the new state of soft clay flow into the hole hole maintain the stability of the wall is difficult and interface friction is low, technology economic efficiency is not ideal, so also should not be used. (7) soil nail not appropriate for corrosive soil such as coal cinder, coal ash and slag, acidic waste products from mineral soil for permanent retaining structures. THE BASIC PRINCIPLE OF THE SOIL NAILED WALLThe soil nailed wall of the mechanism The shearing strength of soil is low, tensile strength almost negligible, but the soil has a certain structure integrity, in foundation pit excavation, can put the slope of the critical height of remain upright, but in more than the depth or ground overload will happen when the whole sudden destruction. General slope protection measures are based on retaining of slope protection passive restriction mechanism, to retaining structure under the soil after the lateral pressure, prevent soil whole stability of the damage. The soil nailed wall technology is placed in the soil body length and distribution density of soil nail and soil body work together, make up for their own strength of the shortings of the soil. So through in order to enhance the stability of slope soil their active restriction mechanism on the basis of the posite soil. Not only to improve the effect of soil overall rigidity, to make up for the tensile, soil shear strength low weakness. Through the interaction, the soil structure strength their potential into full play, a change to the slope deformation and destruction of traits, remarkably raised the overall stability, more important is the soil nailed wall by the load process won39。t produce integrity collapse slippery. The mechanism of the soil nail Soil nail in the role of posite soil body have the following: (1) of posite soil nailing soil skeleton of the hoop role the posite soil deformation and restricting soil make a whole. (2) of soil nail and soil to take the soil and the load gravity stress, soil nail share the role, because soil nail has very high tensile shear strength, so the soil into plastic condition, stress gradually to transfer of soil nailing, soil nail share the role is more outstanding. (3) soil nail the stress transfer and diffusion delayed the formation and development of crack area. (4) the constraints of the slope deformation role in slope surface of soil nail and set in the steel spray TongMianBan limit with slope excavation unloading and inflation deformation, strengthen the function of the boundary constraints. The design principles and the matters needing attention The soil nailed wall structure used to subentry coefficient of said limit state to carry on the design. Foundation pit supporting structure limit state is divided into the following two kinds: one kind is the bearing capacity of limit state corresponding to the supporting structure to achieve maximum carrying capacity or soil instability, too large deformation, resulting in foundation pit supporting structure or surrounding environmental damage. Another kind is the normal use limit state, corresponding to the supporting structure deformation already hinder underground structure construction or affect the normal use of the foundation pit surrounding environment function. The soil nailed wall design calculation to consider foundation pit wall security level we adopt different importance coefficient r. the soil nailed wall as the foundation pit supporting structure form should carry on the carrying capacity of the calculation of the limit state, including tensile bearing capacity of soil nailing the soil nailed wall overall stability checking。 CongLve calculation formula. excavation scheme, and soil nailing wall scheme to fully familiar with the prior to the perimeter of the foundation pit and environment conditions. Such as the foundation pit excavation influence within the scope of the original buildings, structures, road, underground facilities, all kinds of underground pipeline, light is in geotechnical engineering and underground water as well as the edge of the slump, the soil deformation dangers to have full estimation, and necessary protection measures. Usually on the surrounding drainage, cut water, reduce the ground water level and a nearby building settlement observation of underground pipeline, the path, the sinking, deformation, prevent pipeline rupture should take the monitoring, prevent accident39。 ~ 20 176。 The soil nailed wall wall should be adopted in the mortar or concrete protective, top and slope toe should set drainage measures, slope surface can be set up according to the specific conditions discharge water holes. 翻譯：概念土釘墻是由天然土體通過土釘墻就地加固并與噴射砼面板相結(jié)合，形成一個(gè)類似重力擋墻以此來抵抗墻后的土壓力；從而保持開挖面的穩(wěn)定，這個(gè)土擋墻稱為土釘墻。土釘墻的做法與礦山加固坑道用的噴錨網(wǎng)加固巖體的做法類似，故也稱為噴錨網(wǎng)加固邊坡或噴錨網(wǎng)擋墻。10年后出現(xiàn)了錨桿構(gòu)造墻，它是利用砼構(gòu)件排列在開挖過程中的土層表面，用錨桿進(jìn)行背拉，這是一種可以與挖方工程同時(shí)進(jìn)行作業(yè)的方式。70年代出現(xiàn)了土釘墻，1972年法國承包商在法國凡爾賽市鐵路邊坡開挖進(jìn)行了成功應(yīng)用。 　?。?） 施工設(shè)備簡單，由于釘長一般比錨桿的長度小的多，不加預(yù)應(yīng)力所以設(shè)備簡單。 　?。?） 施工不需單獨(dú)占用場地，對現(xiàn)場狹小，放坡困難，有相鄰建筑物時(shí)顯示其優(yōu)越性。 　?。?） 施工噪音、振動小，不影響環(huán)境。 土釘墻的應(yīng)用領(lǐng)域　　土釘墻不僅應(yīng)用于臨時(shí)支護(hù)結(jié)構(gòu)，而且也應(yīng)用于永久性構(gòu)筑物，當(dāng)應(yīng)用于永久性構(gòu)筑物時(shí)，宜增加噴射砼面層的厚度并適當(dāng)考慮其美觀，目前土釘墻的應(yīng)用領(lǐng)域主要有： 　　（1） 托換基礎(chǔ) 　?。?） 基坑支擋或豎井 　?。?） 斜坡面的擋土墻 　?。?） 斜坡面的穩(wěn)定 　　（5） 與錨桿擋墻結(jié)合作斜面的防護(hù) 　　鉆孔注漿型土釘墻系逐層向下開挖方式，每一臺階高度為1～2米，在施工土釘桿、面層噴射砼期間，坡段處無支撐狀態(tài)下需能保持自立穩(wěn)定，因此主要適用于： 　　（1） 有一定粘結(jié)性的雜填土、粘性土、粉土、黃土與弱膠結(jié)的砂土邊坡。 　?。?） 對于標(biāo)準(zhǔn)貫入擊數(shù)（N）低于10擊的砂土邊坡采用土釘法一般不經(jīng)濟(jì)。 　?。?） 對于含水豐富的粉細(xì)砂層，砂卵石層土釘法是不行的。 　?。?） 土釘不適宜在腐蝕性土如煤渣、煤灰、爐渣、酸性礦物廢料等土質(zhì)作永久性支擋結(jié)構(gòu)。一般護(hù)坡措施均基于支擋護(hù)坡的被動制約機(jī)制，以擋土結(jié)構(gòu)承受其后的土體側(cè)壓力，防止土體整體穩(wěn)定性破壞。因此通過以增強(qiáng)邊坡土體自身穩(wěn)定性的主動制約機(jī)制為基礎(chǔ)的復(fù)合土體。通過相互作用、土體自身結(jié)構(gòu)強(qiáng)度潛力得到充分發(fā)揮，改變了邊坡變形和破壞的性狀，顯著提高了整體穩(wěn)定性，更重要的是土釘墻受荷載過程中不會發(fā)生素土邊坡那樣的突發(fā)性塌滑，土釘墻不僅延遲塑性變形發(fā)展階段，而且具有明顯的漸進(jìn)性變形和開裂破壞，不會發(fā)生整體性塌滑。 　?。?