Application of Controllable Splitting Grouting Technology in Loess Foundation Reinforcement

Taking the foundation settlement accident of a large heating boiler foundation in a city in collapsible loess area as an example, controllable splitting grouting can be achieved by controlling the grouting pressure, grouting pipe opening form, grouting volume and grouting method etc., so as to stabilize foundation settlement and improve foundation bearing capacity, for the boiler with large uneven settlement, for boilers with large uneven settlement, quicklime piles are used to jack up the foundation after splitting grouting to stabilize the foundation, the foundation is lifted with quicklime piles after splitting grouting to stabilize the foundation. The results show that the grouting amount of soil is within the design range, the grout splits in the soil several times to form a slurry vein, the settlement is stable after boiler reinforcement, the quicklime method can jack up the foundation and reduce the uneven settlement of the foundation, and the use of controllable splitting grouting can basically eliminate the slight collapsibility grade loess, which provides a new idea for solving the similar problem of uneven settlement of collapsible loess foundation buildings.

Comparative Study of the Field Performances of Pressure-Grouted Micropiles Using Gravity and Packers

When underground space requires excavation in areas below the water table, the foundation system suffers from buoyancy, which leads to the uplifting of the superstructure. A deep foundation system can be used; however, in cases where a hard layer is encountered, high driving forces and corresponding noises cause civil complaints in urban areas. Micropiles can be an effective alternative option, due to their high performance despite a short installation depth. Pressurized grouting is used with a packer to induce higher interfacial properties between micropile and soil. In this study, the field performance of micropiles installed using gravitational grouting or pressure-grouted using either a geotextile packer or rubber packer was comparatively evaluated by tension and creep tests. Micropiles were installed using pressure grouting in weak and fractured zones. As results, the pressure-grouted micropiles showed more stable and stronger behaviors than ones installed using the gravitational grouting. Moreover, the pressure-grouted micropile installed using the rubber packer showed better performance than the one using the geotextile packer.

Understanding the Effect of Cementitious Grouting Pressure on Micro-Fracture Permeability for Rock Reinforcement Underground: A Lab Study

In grouting support projects, due to the small concealment of micro-fractures, the support effect often fails to meet design requirements. The percolation effect is a common factor that causes grouting failure, and the influence of grouting pressure on the percolation effect is very obvious. In this article, a design of a micro-fracture grouting experimental system is presented that can realize high-pressure grouting and then uses a variety of ultrafine cements to carry out high- and low-pressure grouting tests under different fracture opening conditions, thereby obtaining the grouting pressure and accumulated grouting weight during the grouting process. The results show that a combination of the grouting pressure curve and the cumulative grouting weight curve can determine whether the ultrafine cement will have a percolation effect. Increasing the grouting pressure can reduce the critical fracture opening value and also reduce the occurrence of the percolation effect. The research results provide a theoretical basis for the high-pressure grouting of micro-fracture rock masses and offer certain guiding significance for the design of high-pressure grouting support schemes.

Prediction of Grouting Penetration Height Along the Shaft of Base Grouted Pile

Post-pressure grouting is an effective method to improve bearing capacity of ordinary bored cast-in-situ piles. The migration of the grout along the pile side is regarded as an important mechanism responsible for the improvement of the pile capacity. Research into the penetration height of the grout is of great important in evaluating the behavior of base grouted piles. In this paper, a prediction method of grouting penetration height along the shaft of the base grouted pile was proposed. Considering the balance and losses of the grout pressure during grouting, an iterative procedure was given to determine the penetration height of the grout in layered soils. Field test results were also provided to indicate the validity of the proposed method.

KAJIAN PERBAIKAN STRUKTUR PERKERASAN KAKU MENGGUNAKAN METODE PRESSURE GROUTING DENGAN MATERIAL POLYURETHANE DAN EPOXY (Studi Kasus : Ruas Jalan Patriot – Perintis Kemerdekaan Kota Pekalongan)

Today the implementation of road infrastructure development using concrete pavement is experiencing rapid development because it can serve heavy and heavy traffic loads. But there are some problems that often arise in the use of concrete for pavement, causing damage (cracks). Repair of concrete cracks using pressure grouting method is one solution that can be used to improve the strength of concrete. This study discusses the comparison of the effectiveness of using polyurethane and epoxy materials in an effort to improve the rigid pavement structure. The research method used was to carry out repairs to the concrete structure on the Independence Patriotic-Road Section of Pekalongan City using polyurethane and epoxy materials. In this study each of the 5 existing normal (non-damaged) concrete samples, concrete repaired with polyurethane material and repaired concrete using epoxy material using core drill method, which will then be tested for compressive strength in the laboratory, as well as hammer test testing. to find out the strength of the existing concrete damage. The results showed that the average compressive strength of normal existing concrete (not damaged) amounted to 59.20 N/mm2, the average compressive strength of concrete that experienced cracks was 27.04 N/mm2, the average compressive strength value of repair concrete using polyurethane material is 31.92 N/mm2 (increasing by 15.17%) and the average compressive strength of concrete repair using epoxy material is 45.22 N/mm2 (increased by 56.53%).