PowerPoint Presentation

undefined. DIAPHRAGM WALL. DW 01: Theory of Diaphragm wall.

[Audio] What is Diaphragm Wall? The use of slurry trench walls as structural Diaphragm Walls (D’ Wall) in the construction of cut-and-cover metro structures in the late 1950 seconds. They are continuous concrete walls built below the ground level before the commencement of excavation. Diaphragm walls were used for the first time in the top-down sequence in the construction of the Milan Metro. For this reason this method came to known as the Milan Method. The use and popularity of diaphragm walls to be recognized worldwide as important elements in the cut-and-cover construction especially where control of ground movements is critical. They can be used in almost any soil any depth limited only by the capability of the equipment. However as compared to other ground support systems diaphragm walls can be relatively expansive. Slide: 2.

[Audio] Definition of Diaphragm Wall Diaphragm walls are one of the most important technologies of special foundation engineering. A diaphragm wall is constructed using a trench excavated in ground and supported by a mud fluids (typically bentonite or polymer mud) until the mud is replaced by concrete after the steel cage installation. The standard widths are 100200 millimeters for cut-off walls and 450 1200 millimeters for structural members. (as per IS: 9556 – 1980) Slide: 3.

[Audio] D’ Wall – Pictorial reference Slide: 4. D’ Wall – Pictorial reference.

[Audio] Factors affecting D’ Wall Installation of a Diaphragm Wall involves the construction to the required depth of a series of wall panels of predetermined thickness and length. The thickness is determined by the requirements of the design in respect of both the temporary and the permanent loadings and boundary conditions. However the length is decided by the aspects related to the practicalities of construction such as: ground and groundwater conditions stability of the trench extent of the concrete pour before any significant stiffening or setting occurs minimize the movements of the surrounding ground and the structures. Slide: 5.

[Audio] steps involved in the construction D’ wall The steps involved in the construction of a typical diaphragm walls are presented in Figure 1. Slide: 6.

[Audio] DIAPHRAGM wall Technique Figure 1: Construction of Diaphragm Wall (Haws 1990) Slide: 7.

[Audio] Diaphragm wall construction sequence Slide: 8.

[Audio] D’ wall Construction in Afcons Diaphragm walls can be constructed to a depth of 150 meters and a width of 0.5 to 1.50 meters. AFCONS possess a handful experience of in constructing diaphragm walls up to a depth of 55 meters & barrette of 62 meters in Kolkata. AFCONS first constructed their concrete diaphragm wall at Ukai Project in Gujarat in 1964. AFCONS were the pioneers to introduce the diaphragm wall as a waterfront structure for the first time in India. Prestigious Buildings in Mumbai where AFCONS executed Diaphragm Wall are: Air India Terminal Building Office Building For New India Assurance Co. Ltd Hotel Oberoi Sheraton I-L-F-S Office Building At Bandra Kurla Complex Slide: 9.

[Audio] Advantages of D’ Wall Large depth: Methods of construction of D’Wall allows greater depths to be executed. Small Ground Surface Settlement: Settlement of small ground area can be controlled by a diaphragm wall which is essential in congested/crowded area. Strong Adaptability: D-walls can be applied to foundations retaining walls pile foundations and so forth and in different dimensional shapes. Slide: 10.

[Audio] Convenient top-down method construction: D-walls can combine with top-down methods of construction to control the deformation/settlement of adjacent buildings and underground structures. Can be used as a deep foundation: D-walls help to meet the requirement of machine shafts being used as the structural foundation of a ventilation shaft. Slide: 11.

[Audio] Terms used in the D’ Wall construction Slurry trench: Civil Engineering work performed under the protection of a slurry trench or diaphragm wall Panel: Section of a diaphragm wall which is concreted as a single unit. Trench: narrow trench prepared under the protection of a slurry. Cut-off wall: an impervious curtain to stop or reduce the seepage of water Slide: 12.

[Audio] Guide wall: a shallow wall made from the ground level for t0 provide alignment and regulate drilling fluid used for D’wall construction. Stop end tube: a pipe to ensure watertight joints between adjacent panels as false work. Trenching tool: a tool operated from the rig to excavate the soil or rock. Slurry (mod stabilizing fluid): a suspension of definite properties to be filled in the trench during the excavation of D’wall. Contaminated slurry ( contaminated mud churned mud sludge slurry with cuttings): the slurry containing soil or rock cuttings excavated from the trench. Slide: 13.

[Audio] D’ Wall Construction Challenges Logistic management in densely populated zone Minimizing the time cycle Maintaining alignment of couplers used for reinforcement Stability of trench during grabbing operation Maintaining verticality of trench Cage lifting Slide: 14.