本文選題：邊坡工程 + 微型樁　； 參考：《中國鐵道科學研究院》2014年碩士論文

【摘要】：邊坡工程涉及公路、鐵路、礦山、水利水電、核電等眾多工程領(lǐng)域，其中病害邊坡的雨季搶險及滑坡引起的線路保通等工程普遍存在工期緊、施工場地受限等特點。抗滑樁、預應力錨索框架等傳統(tǒng)大型防治結(jié)構(gòu)的施工期周期長、圬工量大，無法滿足快速治理的要求。因此，基于應急搶險和環(huán)保施工的需要，抗滑結(jié)構(gòu)逐漸趨于向輕型化、快速化以及機械化方向發(fā)展，邊坡工程界積極研發(fā)輕型支護體系以及組合型邊坡支擋結(jié)構(gòu)。微型樁由于具有非開挖施工、對土層適用性強、樁位布置靈活、施工速度快、對滑體擾動小等優(yōu)點，近年來在邊坡加固和滑坡治理尤其是一些應急搶修工程中得到了越來越廣泛的應用。但由于微型樁長徑比大、抗彎承載力不足，在外力作用下易產(chǎn)生側(cè)向撓曲變形，作為獨立措施加固邊坡時難以嚴格控制變形。例如，加固隧道穿越的滑坡體時隧道-滑坡體系的變形仍易超出道路安全運行的允許位移量。因此，工程實踐中通常將微型樁與其它滑坡支擋結(jié)構(gòu)聯(lián)合應用以達到防治邊坡滑坡的目的，微型樁的應用推廣仍具有一定的局限性。所以在現(xiàn)有微型樁的應用研究基礎(chǔ)上，積極開發(fā)高承載力的微型樁結(jié)構(gòu)新形式具有重大意義。 本文主要依托科技部科研院所技術(shù)開發(fā)研究專項資金《災后邊坡病害快速治理新結(jié)構(gòu)及防護技術(shù)》（2009E123201），對課題組提出的一種微型樁-錨組合抗滑新結(jié)構(gòu)進行研究。在國內(nèi)外相關(guān)研究的基礎(chǔ)上，結(jié)合堆積層滑坡、堆載誘發(fā)型均質(zhì)土滑坡及黃土滑坡三類典型災害性滑坡，通過現(xiàn)場調(diào)查、理論分析、數(shù)值模擬、室內(nèi)模型試驗相結(jié)合的方法，，對普通微型樁結(jié)構(gòu)及微型樁-錨組合新結(jié)構(gòu)的加固效果及力學機理等進行了系統(tǒng)研究。研究表明微型樁-錨組合新結(jié)構(gòu)應用于滑坡防治是可行的。取得的主要成果如下： （1）在系統(tǒng)總結(jié)實踐中常用的微型樁結(jié)構(gòu)類型的基礎(chǔ)上，基于綜合利用排樁剛架結(jié)構(gòu)與拉錨式擋土結(jié)構(gòu)兩種結(jié)構(gòu)形式優(yōu)點的研發(fā)思路，提出了一種微型樁-錨組合抗滑新結(jié)構(gòu)。該結(jié)構(gòu)以預應力錨索作為外拉系統(tǒng)，一端通過樁頂系梁與微型樁相連，另一端錨固在穩(wěn)定土層中，形成主動加固體系。改進的抗滑機理主要體現(xiàn)在：一方面，增大了剛架式擋土結(jié)構(gòu)體系的側(cè)向剛度，有效限制了結(jié)構(gòu)的整體側(cè)向變形；另一方面，擋土結(jié)構(gòu)所承受的部分荷載，通過預應力錨索傳遞到錨固體周圍穩(wěn)定地層中，充分發(fā)揮了結(jié)構(gòu)的整體受荷能力和地層的自承能力。 （2）以一典型的折線型堆積層滑坡為工程對象，運用FLAC3D有限差分軟件對微型樁-錨組合結(jié)構(gòu)應用于滑坡防治的適宜性進行數(shù)值試驗研究。分別計算了自然工況和普通平面剛架式微型樁結(jié)構(gòu)及微型樁-錨組合結(jié)構(gòu)兩種防治方案加固該滑坡時的坡體變形、應力-應變特征和結(jié)構(gòu)內(nèi)力、外力分布規(guī)律及變形特性。對比分析得出，相比微型樁框架結(jié)構(gòu)，新結(jié)構(gòu)加固的邊坡位移場、應力場、應變場的穩(wěn)定性更好，新結(jié)構(gòu)樁頭位移小，與邊坡協(xié)調(diào)變形性能優(yōu)越，樁體內(nèi)、外力分布相對均勻且峰值有所降低。 （3）通過室內(nèi)地質(zhì)力學模型試驗，對獨立布置的微型樁、垂直布置的平面剛架式結(jié)構(gòu)、傾斜布置的平面剛架式結(jié)構(gòu)及預應力錨索作用下垂直和傾斜布置的平面剛架式組合結(jié)構(gòu)共計五種結(jié)構(gòu)的支擋效果及機理進行研究。結(jié)果表明，微型樁單樁的抗滑機理由抗剪、抗彎及獨特的抗拔性能體現(xiàn)；在群樁頂部增設系梁可增強結(jié)構(gòu)的整體性，形成樁土復合結(jié)構(gòu)；樁軸傾斜至與滑面呈垂直角度時可增加結(jié)構(gòu)的抗剪、抗彎性能，因此針對不同的滑面形態(tài)選擇合適的布置角度可有效提高微型樁抗滑效果；在剛架結(jié)構(gòu)頂部增設預應力錨索可有效增加結(jié)構(gòu)整體剛度，限制側(cè)向變形和樁頭位移，均勻受力分布并減小內(nèi)力峰值。根據(jù)模型試驗結(jié)果，建議在新結(jié)構(gòu)設計中樁錨荷載分擔比取0.4～1.0。 （4）基于新結(jié)構(gòu)為橫向受力的復合抗滑樁的假設，根據(jù)橫向約束的Winkler彈性地基梁計算方法，按變形協(xié)調(diào)原理推導了微型樁-錨結(jié)構(gòu)加固邊坡時錨索拉力、樁身位移及內(nèi)力的計算公式。在此基礎(chǔ)上，提出了微型樁-錨組合結(jié)構(gòu)的一種設計方法及步驟。 （5）以新疆省道S316線一處路基黃土邊坡為工程背景，對新結(jié)構(gòu)的設計步驟進行了詳細介紹。首先根據(jù)理正軟件的邊坡穩(wěn)定性分析模塊計算搜索最危險滑動面；然后計算滑坡推力；在擬定樁截面形式后，通過檢算樁間土拱效應和擾流現(xiàn)象，確定組合結(jié)構(gòu)間距；基于工程實踐經(jīng)驗和相關(guān)規(guī)范要求，確定聯(lián)系梁設計形式及尺寸；通過樁錨荷載分擔比確定錨索設計荷載，計算錨固長度；最后基于樁截面極限抗力通過推導的解析公式計算樁長。
[Abstract]:Slope engineering involves many engineering fields, such as highway, railway, mine, water conservancy and hydropower, nuclear power, etc., in which the rainy season and landslides caused by the landslide are widely used in engineering, such as tight construction time, limited construction site and so on. The construction period of the large control structure, such as anti slide pile, prestressed anchor cable frame and so on, has long period of construction and large quantity of masonry. The method meets the requirements of rapid management. Therefore, based on the needs of emergency emergency rescue and environmental protection construction, the anti sliding structure has gradually tended to light, rapid and mechanized. The slope engineering community has actively developed a light support system and a combined slope retaining structure. The micro pile is characterized by a non excavation construction, strong applicability to the soil layer and a pile position. With the advantages of flexible arrangement, fast construction speed and small disturbance to the slide body, it has been used more and more widely in slope reinforcement and landslide treatment in recent years, especially in some emergency repair projects. However, due to the large length diameter ratio and insufficient bending bearing capacity of the micro pile, it is easy to produce lateral deflection under external force, as an independent measure to reinforce the slope. It is difficult to control the deformation strictly. For example, the deformation of the tunnel landslide system is more likely to exceed the allowable displacement of the road safe operation when the tunnel is strengthened through the landslide. Therefore, the micro pile is usually combined with other landslide retaining structures to prevent the slope landslide. Therefore, based on the applied research of the existing micro piles, it is of great significance to actively develop new forms of micro piles with high bearing capacity.
This paper mainly relies on the new structure and protection technology for the rapid control of post disaster slope diseases (2009E123201), which is based on the special funds of the technical development research of the scientific and Technological Research Institute of the Ministry of science and technology. Three typical catastrophic landslides of slope and loess landslide are systematically studied through field investigation, theoretical analysis, numerical simulation and indoor model test. The reinforcement effect and mechanical mechanism of the new structure of ordinary micro pile and micro pile anchor combination are systematically studied. The study shows that the new structure of micro pile anchor combination is applied to the prevention and control of landslide. It is feasible. The main achievements are as follows:
(1) on the basis of the type of micro pile structure commonly used in the systematic summary practice, based on the research and development ideas of the advantages of the two structural forms of the pile rigid frame structure and the anchorage retaining structure, a new type of micro pile anchor combination anti sliding structure is put forward. The structure is used as the prestressed anchor cable as the external pull system, and one end passes the pile top system beam and the minitype. After the pile is connected and the other end is anchored in the stable soil layer, the active reinforcement system is formed. The improved anti sliding mechanism is mainly embodied in: on the one hand, the lateral stiffness of the rigid frame retaining structure is increased, the overall lateral deformation of the structure is restricted effectively; on the other hand, the partial load of the retaining structure is transferred to the anchor through the prestressed anchor cable. In the stable surrounding strata, the overall loading capacity of the structure and the self bearing capacity of the strata are fully realized.
(2) taking a typical folded stacking landslide as an engineering object, the FLAC3D finite difference software is used to study the suitability of the micro pile anchor combination structure for the landslide prevention and control. The natural working condition, the ordinary rigid frame type micro pile structure and the micro pile anchor combination structure are respectively calculated and two kinds of prevention and control schemes are used to reinforce the slide. The slope deformation, stress strain characteristic and structural internal force, external force distribution law and deformation characteristics. Compared with the micro pile frame structure, the stability of the displacement field, stress field and strain field strengthened by the new structure is better, the displacement of the pile head is small, the deformation performance of the new structure is small, the deformation of the new structure is superior, the distribution of the internal force in the pile is relative to the pile, and the distribution of the force in the pile is relative to the pile. It is uniform and the peak value is reduced.
(3) through the laboratory geomechanics model test, the supporting effect and mechanism of five kinds of rigid frame structure, flat rigid frame structure, flat rigid frame structure and the vertical and inclined plane rigid frame combined structure under the action of prestressed anchor cable are studied. The anti sliding mechanism of pile is reflected in shear resistance, bending resistance and unique anti drawing performance. Adding a beam to the top of the pile group can enhance the integrity of the structure and form a composite structure of pile and soil. When the pile shaft inclines to the vertical angle to the slide surface, it can increase the shear and bending properties of the structure. Therefore, it is effective to select the appropriate layout angle for different sliding surfaces. Increasing the anti sliding effect of the micro pile, adding the prestressed anchor cable on the top of the frame structure can effectively increase the overall stiffness of the structure, limit the lateral deformation and the pile head displacement, the uniform force distribution and reduce the internal force peak. According to the model test results, it is suggested that the ratio of the pile anchor load to the load ratio of 0.4 to 1.0. in the new structure design is suggested.
(4) based on the hypothesis of the composite anti slide pile with the lateral force of the new structure, according to the lateral constraint Winkler elastic foundation beam calculation method, the formula of the anchor cable tension, the pile displacement and the internal force is derived according to the deformation coordination principle. On this basis, a design side of the micro pile anchor combination structure is put forward. Law and steps.
(5) taking a roadbed loess slope in the S316 line of Xinjiang provincial highway as the project background, the design steps of the new structure are introduced in detail. First, the most dangerous sliding surface is calculated by the slope stability analysis module of the software, and then the landslide thrust is calculated. After the cross section of the pile is drawn up, the soil arch effect and the disturbing current between the piles are checked. To determine the spacing of the composite structure, the design form and size of the connecting beam are determined based on the practical experience of the engineering and the requirements of the relevant specifications. The anchor length is calculated by the load sharing ratio of the pile anchor, and the length of the anchorage is calculated. Finally, the pile length is calculated based on the analytical formula derived from the ultimate resistance of the pile section.

【學位授予單位】：中國鐵道科學研究院
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TU473.1

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