Deep High-moisture Soil pH Test Equipment and Method

Excessive use of chemical fertilizers in the soil will cause excessive residues of heavy metals, soil hardening and high soil alkalinity. A soil pH tester is generally used to test the soil pH scale to ensure the normal growth of crops. However, the tester cannot be used directly in the case of soil hardening and the soil should be moistened before measurement. In addition, existing soil pH testers can only perform single-point tests, and multiple tests are generally required in order to obtain accurate experimental data. Common deep soil pH test devices are difficult to use and have the problem of inaccurate measurement results due to excessive impurities in the soil in the process of use, resulting in errors in soil analysis which require secondary revision to improve the soil environment. To make up for the defects of existing technologies, this study designs a deep high-moisture soil pH tester, which has the advantage of high soil impurity filtering performance and addresses the problem of inaccurate measurement results due to excessive impurities in the soil.

Assessment of clay soils strengthening under triaxial cyclic loading

One of the main issues in the design of foundations is the correct forecast of the development of long-term deformations (settlement) of the foundations. Among the main factors affecting settlement, one can single out the neglect of changes in the rheological parameters of the soil in time and the neglect of the loading regime, as well as the processes of soil hardening in time. The work presents the results of a study of the behaviour of samples of clayey soil with a disturbed structure under conditions of triaxial cyclic loading, taking into account the strengthening effect. The relevance of the problem of studying the hardening process is associated with the assessment of the deformability and strength of clays with rheological properties. The tests were carried out in a pneumatic stabilimeter with an artificial soil created of paste. After preparing the samples, they were placed in a sealed container until the start of the test for a period of 1 to 5 days. To establish the ultimate strength of the soil, single static loads were carried out at a given value of the uniform pressure. The main control characteristics during the tests were the maximum and minimum values of the cycle voltages. If the sample did not fail during cyclic loading, it was destroyed by a stepped increase in the static load. The dependences of the change in the strength of a clay soil sample during the holding time before the start of the test were obtained at various values of all-round compression and the amplitude of the cycle. The strength of the soil with a change in the holding time increased up to 1.27 times.

Comparison of the results of numerical calculations using modern soil models (Hardening Soil, Hardening Soil Small and Generalized Hardening Soil) with the geotechnical monitoring results

The use of modern soil models is impossible without carrying out a full range of laboratory tests required to determine the initial soil parameters and their further verification. The correctness of these aspects has a significant impact on the final result of numerical modeling. This paper gives a brief overview of the investigated soil models, presents the results of their verification using the geology of St. Petersburg, and compares the results of their verification on the example of the geology of St. Petersburg. Furthermore, the calculation results are compared using verified soil models (Hardening Soil, Hardening Soil Small and Generalized Hardening Soil) and unverified soil models (Hardening Soil) with geotechnical monitoring data. As an example, the authors describe a method intended for modeling the upheaval of the base of buildings of the surrounding development when using Fundex bored piles on an adjacent site.

Improving Construction Engineering Properties of Soils Stabilized by a Cement Binder with Techno-Genic Products

The article considers the method of stabilizing roadbed soils by introducing metallurgical waste in the structure of the composite binder. It was established during the analysis and experimental research that construction engineering properties are improved as a result of the method. The article provides the obtained results of laboratory tests. The optimum amount of ground blast furnace slag as a component to replace part of Portland cement in a soil cement mix is determined. The dependence of strength gain on the hardening time at different proportions of the composite binder is given. The efficiency of the considered method of soil hardening is estimated.

Influence of parameters in soil hardening model on deformation of excavation

Based on the data of the soil and enclosure structure of a certain excavation, a PLAXIS model was established. The actual monitoring results are compared with the PLAXIS calculation results to verify the reliability of the model. On this basis, the six main parameters in the soil hardening model were changed by a single variable method to obtain the influence of each parameter on the deformation of the excavation. As the soil weight or Poisson’s ratio increases, the lateral displacement of the retaining wall increases. With the increase of the secant modulus or cohesive force or internal friction angle of the soil, the lateral displacement of the retaining wall decreases. The power index m has basically no effect on the lateral displacement of the retaining wall. With the increase of m, the settlement of the soil gradually increases uniformly.

ANALISIS DEFORMASI GALIAN DALAM PADA TITIK TEPI DINDING DIAFRAGMA DENGAN METODE ELEMEN HINGGA MELALUI STUDI EVALUASI MODEL TANAH

Banyaknya pembangunan infrastruktur yang merupakan salah satu tolak ukur kemajuan suatu daerah menyebabkan terjadinya penyempitan lahan didaerah tersebut. Sehingga pemanfaatan ruang dan lahan sangat dibutuhkan untuk menunjang kemajuan pesatnya pembangunan infrastruktur. Salah satu inovasi terbaik dalam mengatasi masalah keterbatasan lahan adalah membuat bangunan bawah tanah sehingga memberi ruang yang lebih untuk pembangunan. Pembangunan yang cukup terbaru di Indonesia saat ini adalah pembangunan MRT (Mass Rapid Transit) yang dilakukan di Jakarta. Pembangunan ini dalam pelaksanaannya membutuhkan proses konstruksi terowongan (tunneling) dan galian dalam untuk tiap stasiunnya. Pada penelitian ini, penulis terpusat terhadap masalah galian dalam pada stasiun Senayan dari proyek konstruksi MRT Jakarta. Permasalahan terbesar dalam suatu pekerjaan galian dalam adalah adanya deformasi lateral pada dinding bangunan bawah tanah dalam hal ini yang digunakan adalah dinding diafragma (D-Wall) dan juga adanya penurunan tanah disekitar galian. Oleh karena itu, perlu dilakukan pengecekan agar tidak terjadi keruntuhan. Metode konstruksi yang digunakan pada stasiun Senayan adalah metode konstruksi Top-Down. Pada penelitian ini dilakukan analisis deformasi horizontal dan penurunan tanah menggunakan software Plaxis 3D dengan dua pemodelan tanah, yaitu model tanah Mohr Coulomb dan Hardening Soil. Hasil deformasi horizontal yang diperoleh menggunakan model tanah Hardening Soil lebih mendekati monitoring dilapangan dibandingkan dengan model tanah Mohr-Coulomb. Penelitian ini berfokus pada bagian-bagian tepi pada dinding diafragma melengkapi jurnal sebelumnya yang berfokus pada titik tengah dari dinding diafragma. Besarnya deformasi horizontal pada tahap akhir galian (penimbunan kembali tanah hingga dasar muka tanah) di titik P#80 (di tepi dinding diafragma) tercatat pada monitoring inclinometer sebesar 4.15 mm, dan deformasi yang dihasilkan menggunakan model Hardening Soil sebesar 9.57 mm sedangkan menggunakan model Mohr-Coulomb sebesar 16.05 mm. Hasil deformasi horizontal yang diperoleh menggunakan model tanah Hardening Soil lebih mendekati monitoring dilapangan dibandingkan dengan model tanah Mohr-Coulomb meskipun hasil yang diperoleh cukup jauh dari monitoring dilapangan. Kata Kunci : Galian Dalam, Deformasi Horizontal, Model Mohr Coulomb, Model Hardening Soil, Plaxis 3D The number of infrastructure development which is one of the benchmarks of the progress of a region causes the narrowing of land in the area. So that the utilization of space and land is needed to support the rapid progress of infrastructure development. One of the best innovations in overcoming the problem of land limitations is to make the underground building giving more space for development. The most recent development in Indonesia today is the construction of MRT (Mass Rapid Transit) conducted in Jakarta. This development in its implementation requires tunneling and deep trenching process for each station. In this study, the authors centered on the deep trenching problems at the Senayan station from the Jakarta MRT construction project. The biggest problem in a deep trenching work is the lateral deformation of underground building walls in this case which is used diaphragm wall (D-Wall) and also the decrease of soil around the excavation. Therefore, it is necessary to check to avoid collapse. The construction method used in Senayan station is a Top-Down construction method. In this research, horizontal deformation and soil degradation analysis using Plaxis 3D software with two soil modeling, Mohr Coulomb and Hardening Soil soil model. The result of the horizontal deformation obtained using Soil Hardening Soil model is closer to monitoring the field compared to the Mohr-Coulomb soil model. This study focuses on the edges of the diaphragm wall complementing the previous journal focusing on the midpoint of the diaphragm wall. The magnitude of the horizontal deformation at the final stages of excavation (backfill) to P # 80 (on the edge of the diaphragm wall) was recorded in inclinometer monitoring of 4.15 mm, and the resulting deformation using the Hardening Soil model of 9.57 mm while using the Mohr model -Coulomb of 16.05 mm. The horizontal deformation results obtained using the Soil Hardening Soil model is closer to the field monitoring than the Mohr-Coulomb soil model although the results obtained are quite far from the field monitoring.Keywords: Deep Excavation, Horizontal Deformation, Mohr Coulomb Model, Hardening Soil Model, Plaxis 3D.